Required introduction: This article can be considered both as a “guide to action” and as simply an attempt to explain the principles of operation ABS systems for all those who have not yet encountered or have just begun to study this system. Do not look here for answers to all the questions that arise, because, as practice shows, such “nuances” always arise, the solution of which requires not blindly following the instructions or advice given here, but applying " technical cunning" and take this article only as a basis or as a "push for reflection."
Vladimir Petrovich
Yuzhno-Sakhalinsk
...The client was pale and talkative. The right wing of his “swallow” was crushed, which is why his Lexus, which previously had an “arrogant” look, now looked like a beaten mongrel...
The client spoke a lot and quickly, and from his conversation it gradually became clear that “he was walking as usual, in the left lane and no more than 80 kilometers. Someone cut him off and he had to go to the right, and so as not to hit the Niva, then slow down... and then the car took off, despite the existing ABS system. And, in order not to hit another car that was sparkling with varnish, I had to “grind” to the curb. And there it was...”
We remembered this client. Firstly, quite fresh and very well maintained car, and secondly, he came to us not for repairs, but so that we could simply check “how the engine works and whether everything is fine with it.”
...We begin to check the performance of the ABS system. It must be said that from practice we have learned the following for ourselves: malfunctions in the ABS system can be “static” and “dynamic”.
“Static” are those whose cause constantly “sits” in the memory of the on-board computer. For example, a broken wire to the sensor, a jammed electric motor of the hydraulic modulator, a faulty sensor or sensors itself ("sensors" are extremely rare, usually one sensor fails, but if several would fail at once, this only happened once...) .
“Dynamic” malfunctions are those that are detected only when driving, when the “decision-making speed” is reached - 10 km/h. It is this speed that is adopted by the Japanese developers of ABS systems and is “stored in the memory” of the ABS computer as a speed at which the computer “needs to decide” how well and “correctly” the ABS system works and whether it will ensure safe movement in the future.
The ABS system itself works as follows: when the ignition is turned on, the ABS system computer “wakes up” and begins to “interrogate” the speed sensor, the modulator, all circuits and itself for serviceability and “readiness for work.” At this time, the instrument panel lights up ABS light bulb. All this takes 1-2 seconds, and if everything is normal, then after the “questioning” the ABS computer “calms down” and turns off the light on the panel. If somewhere in the ABS system a “static” malfunction is detected in the form of a broken wire, a faulty sensor, and so on, the ABS light on the instrument panel continues to light and “tells” us that “driving cannot be started, a failure has occurred in the ABS system.” .Figure it out."
If the ABS light comes on after reaching the “decision speed”, this is already a “dynamic” malfunction and it can occur, for example, due to the fact that some wheel sensor incorrectly reads the “driving information” or does not “read it” at all. . Here the reason may be that, for example, the air gap (Air Gap) between the speed sensor and the gear on the hub is larger permissible limits. Or itself gear The hub has chips. In any case, you need to carry out a self-diagnosis procedure and “determine yourself.”
For this purpose, Toyota, as well as other brands of cars, has a so-called “self-diagnosis block”.
Let's open it. The contacts are marked on the inside of the cover. Let's find "Tc - E1". However, let's not rush, because if we immediately jump these contacts, we may not get the trouble code we need. We also need to find the contacts “Wa - Wb”, which are closed by a short pin (Short Pin)
This pin must be pulled out to perform self-diagnosis of the ABS system. Now you can close contacts Tc - E1. Below is a breakdown of Toyota ABS fault codes (however, do not assume that the following fault codes are suitable for ALL Toyota vehicles):
| 11 | solenoid valve relay circuit open |
| 12 | short circuit in the solenoid valve relay circuit |
| 13 | open circuit in the electric pump relay circuit |
| 14 | short circuit in the electric pump relay circuit |
| 15 | short circuit or open circuit TRAC solenoid reley |
| 21 | open or short circuit in the right solenoid front wheel |
| 22 | open or short circuit in the left front wheel solenoid |
| 23 | open or short circuit in the right solenoid rear wheel |
| 24 | open or short circuit in the left rear wheel solenoid |
| 31 | error in the front right wheel speed sensor signal |
| 32 | error in the left front wheel speed sensor signal |
| 33 | error in the right rear wheel speed sensor signal |
| 34 | error in the left rear wheel speed sensor signal |
| 35 | break in the front left/rear right wheel speed sensor |
| 36 | break in the front right/rear left wheel speed sensor |
| 37 | hubs are faulty rear axle |
| 41 | battery voltage is less than 9.5 V or more than 16.2 V |
| 51 | The pump motor of the hydraulic control unit is blocked or the pump motor circuit is interrupted |
| 52 | The pump motor of the hydraulic control unit is blocked |
-Did you do anything with the “hodovka”?
-I changed the pads...
As they say, we have no questions. While the client is swearing and threatening to “tear off the head” of that “specialist,” let’s say that even replacing pads or something else on cars with an ABS system must be trusted to a person who has at least some understanding of the structure and operation of the ABS system. What happened in in this case?
It’s simple: either that “specialist” was in a hurry, or something else, but he didn’t secure the tourniquet on the counter. Then the events developed as follows - Winter, snow, somewhere the roads are wet, with puddles, the car is driving and snow is slowly sticking to the harness dangling near the wheel itself, gradually turning into ice. At first a little, and then more and more, and finally a moment comes when the weight of the adhering ice exceeds the weight of the tourniquet itself, and on every bump or unevenness in the road the tourniquet begins to twitch violently and dangle. That's what fastenings are for...
So what to do? Removing and replacing the sensor? Let's pause. As my old friend Leva Kiperman said: “There is one way...”.
Before you suffer and remove the speed sensor (and removing it is a rather lengthy procedure, because, usually, speed sensors become so “well” soured in the “body” of the hub that you have to pull it out literally millimeter by millimeter) - let’s first check and try to establish the location cliff We know the resistance of the speed sensor - 970 Ohms (plus or minus), so we will proceed from this.
First, disconnect the connector and “sit” on the contacts with a multimeter. Alas, nothing. Then we go further and start checking the resistance on these two wires every 10 - 15 centimeters. It is highly desirable that the probes be sharpened so as to be able to pierce the wire. ...and somewhere in the middle of the harness we found a break. It’s good that in this “convenient” place, and not the sensor itself - then it would have been a bit difficult.
As you can see, the ABS system “by itself” almost never fails.
There will always be a “specialist” who will “help” her. And to prevent this from happening, here's a little advice for you:
Whether your car is “cool” or “ordinary” doesn’t matter. Find one master (workshop) in your city where people “think” and not just “make money.” You'll figure it out. And let them “drive” your car throughout its “life”. And even if this master (workshop) is highly specialized (which is very good!) and they do not perform some work, then before you repair something “outside,” seek advice.
Real, conscientious masters will not give you bad advice.
And finally, some tips and recommendations.
Firstly, “how to delete a fault code?”.
In books they write “many and different things” about this, but you can do it simpler, faster, and more correctly: after eliminating the fault, remove the negative terminal of the battery for 30-40 seconds, and then put it back on. Well, if for some reason it didn’t work out, then in another way:
- tighten the parking brake;
-jumper contacts Tc - E1
-delete fault codes according to the following scheme: press the brake pedal at least 8 times, each time holding the pedal for at least 3 seconds;
-check whether the ABC light shows any code or not.
However, it should be remembered that this method Does not apply to all Toyota models.
You can “diagnose” your car yourself if you carefully read the following:
If sometimes the ABS light comes on when braking, check your tires.
Isn't she "bald"? Because at the moment the brakes are released, the “front” of the car goes slightly upward, and in this case a situation such as an ABS “malfunction” is triggered due to loss of traction.
If the light starts to light up after carrying out any work on the chassis, check the connections of the connectors (the “guys” could simply forget to connect them), the resistance of the sensors - our “chassis” are usually repaired with pry bars, but they tend to slip off and what -to tear or pull. The “teeth” may break when replacing the hub. It's easy to check: remove the sensor, insert something plastic and flexible into the hole and rotate the wheel. And listen. If you have an oscilloscope, then everything will be visible on the screen: where there is no tooth or it is broken, there will be a “failure” in the sequence of output pulses. And on Toyota removed hub everything is visible from the inside.
If the ABS light comes on “sometimes”, and it is useless to look for some kind of cyclicity or pattern in this, because it simply does not exist, then you should check the connections, chips, how the relays sit in the sockets, i.e. quality of contacts. If everything is fine, and the light starts to light up when a certain speed is reached, then first check the cleanliness gear wheels in the hubs. Jack, clean brush in gasoline and rotate, rotate...
If everything is fine again and the light comes on, check the voltage. The ABS block has a transistor B 1015 that stabilizes the voltage (green, in a plastic case), so there should be 4.8-5.1 V at the collector. "Brains" will not work when undervoltage on-board networks.
The serviceability of the ABS system largely depends on how correctly and completely the entire system is filled with hydraulic fluid. Because if the system is even a little “airy,” then this is fraught with unpredictable consequences when emergency braking at high speed, especially on slippery roads.
Below are several symptoms, the appearance of which can, with a certain degree of probability, indicate that the system is “airy,” i.e. about the need to remove air from it.
At speeds above 40 km/h and heavy braking:
The brake pedal noticeably “hits” your foot with the same frequency (several times per second);
Feeling as if the front part of the car is “pounding”;
Hands on the steering wheel feel the impacts and steering wheel jerks from side to side;
The car does not brake “evenly”, but with a skid in some direction.
If you brake at a lower speed and not so sharply, your leg will still feel the impacts brake pedal. All this can be explained in this way: when air enters the system, the hydraulic fluid is no longer “practically incompressible”, since it is “diluted” with air bubbles, which give the effect of a “dip” in the pressure of one or another hydraulic branch. During a “failure” on one wheel, it is blocked by the blocks, while the other wheel works without “failure”.
The system is already unbalanced, but the ECU is trying to work according to the established algorithm, which does not provide for such an incomprehensible situation as the presence of air bubbles in the liquid, which “fail” the system as they please... All these hits of the brake pedal in the leg are an attempt by the “brains” "Coping with an emergency situation.
We begin pumping the system from the farthest wheel from the hydraulic modulator. Everything is as usual - remove the rubber cap from the valve, connect a transparent hose to it, lower it into a container with hydraulic fluid and unscrew (key 10) the valve.
After that:
- Turn on the ignition;
- Press the brake pedal all the way (second person);
- We look at the end of the hose - air bubbles are coming from there;
- Turn off the ignition.
At sharp pressing on the brake pedal and high speed- the foot practically does not feel the pulsation of the brake pedal.
The car brakes smoothly and without skidding.
It should be noted that the reasons for the described situation may be wear and tear. brake disc and faulty shock absorbers.
Well, of course, try every time opportunity(when replacing, for example, brake pads) do preventive maintenance of sensors, i.e. cleaning them from dirt and metal debris that “strives” to become magnetized.
Diagnosis of ABS failures
Control panel connection diagram ABS lampsThe driver is notified of ABS failures by a special warning lamp located on the dashboard car. As soon as the ABS control module detects a violation in the system, it turns it off. The brake system continues to function as normal.
Diagnosis of the ABS condition is carried out every time the engine is started and is accompanied by a short-term activation of the warning lamp. Within a short time after starting, the llama should automatically turn off.
If the ABS warning light comes on and stays on while driving, first make sure that the parking brake is fully released and that the brake system is functioning properly. If everything is normal, then the ABS has failed. First of all, perform the following simple checks:
a) Check the condition brake calipers and wheel cylinders;
b) Check the condition and reliability of fastening contact connectors wiring of the ABS control module and wheel sensors (see Chapter Onboard electrical equipment);
c) Check the relevant fuses (see Chapter Onboard electrical equipment).
ABS warning lamp failures
The cause of failure of the ABS warning lamp may be a break or short circuit in its electrical wiring.
Warning lamp ABS does not activate when ignition is turned on
Try to turn on the ignition without starting the engine - if the other indicator lamps included in the instrument cluster work properly, proceed to the next step of the test, otherwise you should carry out the necessary restoration of the instrument panel.
Turn off the ignition. Remove the instrument cluster, remove the ABS warning lamp and check its condition. If the lamp is burnt out, replace it, otherwise proceed to the next step of the test.
Disconnect contact pair B62/F45 and measure the voltage between chassis ground (-) and terminal No. G6 (+) of connector B62. If the measurement result is less than 3 V, proceed to the next test step, otherwise, check the condition of the wiring of the corresponding warning lamp. Carry out the necessary restorative repairs.
Turn off the ignition, place the indicator lamp being tested in its normal place and install the instrument cluster.
Turn on the ignition and repeat the voltage measurement. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the electrical wiring. Carry out the necessary restorative repairs.
Turn off the ignition and check the voltage between terminal G6 (+) of connector F45 and chassis ground. If the measurement result is less than 3 V, proceed to the next test step, otherwise check the condition of the related wiring. Carry out the necessary restorative repairs.
Turn on the ignition and repeat the test. If the measurement result is less than 3 V, proceed to the next test step, otherwise, check the condition of the wiring of the corresponding warning lamp. Carry out the necessary restorative repairs.
Measure the resistance between terminal No. 23 of connector F49 and ground. If the measurement result is less than 5 ohms, proceed to the next test step, otherwise check the condition of the grounding of the control module/hydraulic modulator assembly. Carry out the necessary restorative repairs.
Measure the resistance between ground and terminal G6 of connector F45. If the measurement result is less than 5 ohms, proceed to the next test step, otherwise check the condition of the connector and its wiring harness. Carry out the necessary repairs and replace the connector if necessary.
Turn off the ignition and check the condition of the contact connectors on the circuit section between the instrument cluster and the ABS control module - if there are no signs of poor contact reliability, replace the ABS control module/hydraulic modulator assembly.
The ABS warning light does not turn off after the engine is started
Turn off the ignition and make sure that the contact connector of the control module/ABS hydraulic modulator is completely seated and securely fixed.
Measure the resistance between chassis ground and each (A and B) of the diagnostic terminals (B81). If the measurement result is less than 5 ohms, proceed to the next step of the test, otherwise check the condition of the relevant wiring harness and make the necessary repairs.
Turn off the ignition and connect the diagnostic terminal to terminal No. 8 of the B82 diagnostic connector. Disconnect the ABS control module connector and measure the resistance between terminal No. 4 of connector F49 and chassis ground. If the measurement result is less than 5 ohms, proceed to the next step of the test, otherwise check the condition of the electrical wiring in the circuit between the ABS control module and the diagnostic connector, and make the necessary repairs.
Start the engine at idle speed and check the voltage between the B (+) terminal on the rear of the generator (power terminal) and chassis ground. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise replace/repair the generator (see Chapter) and repeat the test.
Turn off the ignition and check the condition of the battery pole terminals and the reliability of the wire terminal lugs on them. If necessary, make the necessary corrections.
Disconnect the ABS control module wiring connector, then run the engine at idle speed and measure the voltage between terminal No. 1 (+) of connector F49 and chassis ground. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the power supply circuit wiring. Carry out the necessary restorative repairs.
Disconnect contact pair B62/F45 and turn on the ignition - if the ABS warning lamp does not work, proceed to the next step of the test, otherwise check the condition front tourniquet electrical wiring.
Turn off the ignition and check the condition of the tabs on the control module connector terminals. If the terminals are in order, proceed to the next step of checking, otherwise replace the control module/hydraulic modulator (see Section).
Measure the resistance between terminals No. 22 and 23 of the ABS control module connector. If the measurement result is more than 1 MOhm, proceed to the next test step, otherwise replace the ABS control module/hydraulic modulator assembly (see Section Removing, installing and checking the proper functioning of the ABS control module/hydraulic modulator assembly).
Measure the resistance between terminal G6 of connector F45 and chassis ground. If the measurement result is less than 0.5 Ohm, proceed to the next step of the test, otherwise make the necessary repairs to the electrical wiring.
Connect the wiring harness to the ABS control module and measure the resistance between terminal G6 of connector F45 and chassis ground. If the measurement result is more than 1 MOhm, proceed to the next step of the test, otherwise make the necessary repairs to the electrical wiring.
Check the condition and tightness of the ABS control module connector. If necessary, make the necessary corrections or replace the control module/hydraulic modulator unit.
Unable to read fault codes
If the warning lamp turns on and off normally, but does not display the initial code (DTC 11 - see below) when entering diagnostic mode, turn the ignition switch off and perform the checks.
Wheel sensor failures
Failures of wheel sensors lead to disruption of ABS functioning. The connection diagram for wheel sensors is shown in the illustration.
An open circuit in the wheel sensor circuit or an excessively high input voltage level (DTC Nos. 21, 23, 25 and 27)
Disconnect the wiring harness from the ABS control module and measure the voltage between the appropriate wheel sensor terminal No. 1 and chassis ground. If the measurement result is less than 1 V, proceed to the next test step, otherwise replace the sensor.
Turn the ignition on and repeat the previous check. If the measurement result is less than 1 V, proceed to the next test step, otherwise replace the sensor.
Turn off the ignition and connect the electrical wiring to the sensor. Measure the resistance between terminals Nos. 11 and 12 (DTC 21)/9 and 10 (DTC 23)/14 and 15 (DTC 25)/7 and 8 (DTC 27) of connector F49. If the measurement result does not fall outside the range of 1 ÷ 1.5 kOhm, proceed to the next step of the test, otherwise check the condition of the electrical wiring in the area between the control module and the sensor. Carry out the necessary restorative repairs.
Measure the voltage between ground and terminal No. 11 (DTC 21)/9 (DTC 23)/14 (DTC 25)/7 (DTC 27) of connector F49. If the measurement result is more than 1 V, eliminate the cause. short circuit on the circuit section between the sensor and the ABS control module. If there is no voltage (less than 1 V), turn on the ignition and repeat the test. If there is still no voltage (less than 1 V), proceed to the next test step, otherwise check the condition of the wiring between the sensor and the ABS control module, and if necessary, eliminate the cause of the short circuit.
Measure the gap between the sensor and the rotor along the entire perimeter of the latter. If there is insufficient clearance (see Specifications) adjust it by selecting the adjusting shim (26755AA000). If the gap is too large, remove the spacers and replace the rotor (complete with hinge assembly) or the failed sensor. Having completed the adjustment, proceed to the next step of testing.
Turn off the ignition and measure the resistance between terminal No. 1 of the wheel sensor connector and chassis ground. If the measurement result is more than 1 MΩ, proceed to the next test step, otherwise replace the sensor.
Turn off the ignition and connect the electrical wiring to the wheel sensor. Measure the resistance between chassis ground and terminal No. 11 (DLC 21)/9 (DLC 23)/14 (DLC 25)/7 (DLC 27) of connector F49. If the measurement result is more than 1 MOhm, proceed to the next step of the test, otherwise check the condition of the wiring in the circuit between the sensor and the ABS control module. Carry out the necessary restorative repairs. If the wiring is OK, replace the control module/hydraulic modulator assembly.
Restore the original connections of all connectors, clear the processor memory (see below) and repeat the procedure for reading diagnostic codes. If no changes (for improvement) have occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, proceed to perform the appropriate check. If the failure does not recur, therefore, the malfunction was temporary, once again make sure that all contact connections are securely fastened.
Short circuit in the wheel sensor circuit (DTC No. 22, 24, 26 and 28)
Turn off the ignition and check that the sensor mounting bolts are securely tightened (32 Nm). If necessary, tighten the fasteners and proceed to the next step of testing.
If you are unable to use an oscilloscope, proceed to checking the mechanical condition of the rotor and cleaning the components.
If you have an oscilloscope, jack up the car and place it on jack stands so that the wheels are completely off the ground. Turn off the ignition and connect an oscilloscope between terminals No. C5 (+) and B5 (-) (DTC 22)/C6 (+) and B6 (-) (DTC 24) of connector B62 or 1 (+) and 2 (-) (DTC 26)/4 (+) and 5 (-) (DTC 28) connectors F55.
Turn on the ignition and, while rotating the corresponding wheel of the car, monitor the oscilloscope readings. The amplitude of the sinusoidal signal displayed on the screen should not exceed the range of 0.12 ÷ 1.00 V; if this condition is not met, or the signal has an incorrect shape, proceed to the next stage of testing.
Check the wheel hub runout. If the measurement result is less than 0.05 mm, proceed to the next test step, otherwise replace the hub.
Turn off the ignition. Disconnect the wiring from the appropriate wheel sensor. Measure the resistance between terminals No. 1 and 2 of the sensor connector. If the measurement result does not fall outside the range of 1 ÷ 1.5 kOhm, proceed to the next test step, otherwise replace the sensor.
Measure the resistance between ground and terminal No. 1 of the wheel sensor connector. If the measurement result is more than 1 MΩ, proceed to the next test step, otherwise replace the sensor.
Connect the wiring to the wheel sensor and disconnect it from the ABS control module. Measure the resistance between terminals Nos. 11 and 12 (DTC 22)/9 and 10 (DTC 24)/14 and 15 (DTC 26)/7 and 8 (DTC 28) of the ABS control module connector F49. If the measurement result does not fall outside the range of 1 ÷ 1.5 kOhm, proceed to the next step of the test, otherwise carry out the necessary repairs to the electrical wiring in the circuit between the sensor and the ABS control module/hydraulic modulator.
Measure the resistance between chassis ground and terminal No. 11 (DTC 22)/9 (DTC 24)/14 (DTC 26)/7 (DTC 28) of control module connector F49. If the measurement result is more than 1 MΩ, proceed to the next test step, otherwise check the wiring between the sensor and the module for a short circuit. Carry out the necessary restorative repairs.
Measure the resistance between ground and terminal No. 23 of connector F49. If the measurement result is less than 0.5 Ohm, proceed to the next stage of testing, otherwise eliminate the cause of the grounding quality problem.
Check the tightness of the contact connectors of the ABS control module and the wheel sensor. Make any necessary corrections. If the contacts are OK, proceed to the next step of the test.
Make sure the car phone/remote control transmitter is installed far enough away from the wheel sensor wiring harness.
Restore the original connections of all contact connectors and measure the resistance between ground and terminal No. A5 (DTC 22)/A6 (DTC 24) of connector B62. If the measurement result is less than 0.5 Ohm, proceed to the next test step, otherwise replace the shielded harness.
Restore the original connections of all connectors and repeat the procedure for reading diagnostic codes. If no changes (for improvement) have occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, go to the appropriate test. If the failure does not recur, therefore, the malfunction was temporary, once again make sure that all contact connections are securely fastened.
There are problems related to the proper operation of the wheel sensor (one or all four) issuing an information signal (DTC 29)
Assess the condition of the treads and tire inflation pressure. If necessary, make appropriate corrections/replacements.
Check that the ABS sensor mounting bolts are securely tightened (32 Nm). If necessary, tighten the fasteners and proceed to the next step of testing.
Measure the gap between the sensor and the rotor along the entire perimeter of the latter. If the gap is insufficient (see Specifications), correct it by selecting an adjusting shim (26755AA000). If the gap is too large, remove the spacers and replace the rotor (complete with hinge assembly) or the failed sensor. Having completed the adjustment, proceed to the next step of testing.
If you are unable to use an oscilloscope, proceed to checking the mechanical condition of the rotor and cleaning the components. If you have an oscilloscope, jack up the car and place it on jack stands so that the wheels are completely off the ground. Turn off the ignition and connect an oscilloscope between terminals No. C5 (+) and B5 (-) (DTC 22)/C6 (+) and B6 (-) (DTC 24) of connector B62 or 1 (+) and 2 (-) (DTC 26)/4 (+) and 5 (-) (DTC 28) connectors F55.
Turn on the ignition and, while rotating the corresponding wheel of the car, monitor the oscilloscope readings. The amplitude of the sinusoidal signal displayed on the screen should not exceed the range of 0.12 ÷ 1.00 V; if this condition is not met, or the signal has an incorrect shape, proceed to the next test step, otherwise proceed to the next test.
Carefully inspect the wheel sensor and its rotor for signs of damage or contamination. Clean the components and troubleshoot any problems.
Check the wheel hub runout. If the measurement result is less than 0.05 mm, proceed to the next test step, otherwise replace the hub.
Turn off the ignition. Restore the original electrical wiring connections. Clear the processor memory (see below) and repeat the procedure for reading diagnostic codes. If no changes (for improvement) have occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, go to the appropriate test. If the failure does not recur, therefore, the malfunction was temporary, check again that all contact connections are securely fastened.
ABS control module/hydraulic modulator failures
Malfunction of the intake (DTC 31, 33, 35 and 37)/exhaust (DTC 32, 34, 36 and 38) solenoid valve
Disconnect the wiring from the ABS control module.
Run the engine at idle speed and measure the voltage between terminal No. 1 (+) of the control unit connector F49 and chassis ground. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the electrical wiring between the battery, ignition switch and ABS control module. Carry out the necessary restorative repairs.
Turn off the ignition and measure the resistance between chassis ground and terminal No. 23 of connector F49. If the measurement result is less than 0.5 Ohm, proceed to the next stage of testing, otherwise eliminate the cause of the grounding quality problem.
Malfunction of the ABS control module (DTC 41)
Turn off the ignition. Disconnect the wiring from the ABS control module and measure the resistance between terminal No. 23 of connector F49 and chassis ground. If the measurement result is less than 0.5 Ohm, proceed to the next stage of testing, otherwise eliminate the cause of the grounding quality problem.
Check the condition and reliability of the electrical wiring connectors on the ABS control module, generator and battery. If necessary, make appropriate repairs. If there are no contact quality violations, proceed to the next stage of testing.
Make sure the car phone/remote control transmitter is installed well away from the ABS wiring harnesses.
Turn off the ignition. Restore the original electrical wiring connections. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no changes (for improvement) have occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, go to the appropriate test. If the failure does not recur, therefore, the malfunction was temporary, once again make sure that all contact connections are securely fastened.
Deviation from the nominal supply voltage level (DTC 42)
Start the engine and warm it up to normal operating temperature. Check that the speed is set correctly idle move. Measure the voltage between the B (+) terminal on the rear of the generator and chassis ground. If the measurement result does not fall outside the range of 10 ÷ 17 V, proceed to the next step of the test, otherwise check the condition of the charging system (see Chapter Engine electrical equipment
), make the necessary corrections.
Turn off the ignition and check the condition of the battery pole terminals and the reliability of the wire terminal lugs on them. If necessary, clean the contact surfaces of the terminals/tips. If the terminals are OK, disconnect the wiring from the ABS control module, run the engine at idle speed and measure the voltage between ground and terminal No. 1 (+) of connector F49. If the measurement result does not fall outside the range of 10 ÷ 17 V, proceed to the next step of the test, otherwise check the condition of the wiring between the ignition switch and the contact connector of the ABS control module. Carry out the necessary restorative repairs.
Turn off the ignition and measure the resistance between terminal No. 23 of connector F49 and chassis ground. If the measurement result is less than 0.5 Ohm, proceed to the next stage of testing, otherwise eliminate the cause of the grounding quality problem.
Check the condition and reliability of fixation of the electrical wiring contact connectors on the ABS control module, generator and battery. If necessary, carry out appropriate repairs. If there are no contact quality violations, proceed to the next stage of testing.
Turn off the ignition. Restore the original electrical wiring connections. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no changes (for improvement) have occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, go to the appropriate test. If the failure does not recur, therefore, the malfunction was temporary, once again make sure that all contact connections are securely fastened.
Malfunction of the AT control system (DTC 44)
Turn the ignition switch OFF and disconnect the two transmission control module (TCM) wiring connectors. Also disconnect the wiring from the ABS control module. Measure the resistance between terminal No. 3 of connector F49 and chassis ground. If the measurement result is more than 1 MOhm, proceed to the next test step, otherwise, repair the wiring in the area between the TCM and the ABS control module.
Turn on the ignition and measure the voltage between ground and terminal No. 3 of connector F49. If the measurement result is less than 1 V, proceed to the next test step, otherwise make the necessary repairs to the wiring in the area between the TCM and the ABS control module.
Measure the voltage between ground and terminals No. 3 and 31 of connector F49. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the wiring in the area between the ABS control module and the TCM. Carry out the necessary restorative repairs.
Check the condition and reliability of fixation of the contact connectors of the ABS and AT control modules. If necessary, clean the terminals and proceed to the next test step.
Turn off the ignition. Restore the original electrical wiring connections. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no changes (for improvement) have occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, go to the appropriate test. If the failure does not recur, therefore, the malfunction was temporary, once again make sure that all contact connections are securely fastened.
Valve relay malfunction (DTC 51)
Turn off the ignition and disconnect the electrical wiring from the ABS control unit. Run the engine at idle speed and measure the voltage between terminals No. 1 and 24 of connector F49 of the ABS control module and chassis ground. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the wiring between the ABS control unit and the battery. Carry out the necessary restorative repairs.
Measure the resistance between terminals No. 23 (+) and 24 (-) of the control module connector. If the measurement result is more than 1 MΩ, proceed to the next test step, otherwise replace the control unit.
Check the condition and reliability of fixation of the electrical wiring connectors on the ABS control module, generator and battery. If necessary, carry out appropriate repairs. If there is no violation of the quality of contacts, proceed to the next stage of testing.
Turn off the ignition. Restore the original electrical wiring connections. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no changes (for improvement) have occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, go to the appropriate test. If the failure does not recur, therefore, the malfunction was temporary, once again make sure that all contact connections are securely fastened.
Malfunction of the drive motor/its relay (DTC 52)
Turn off the ignition. Disconnect the wiring harness from the ABS control module, then turn the ignition key back to the ON position and measure the voltage between control module connector F49 terminal No. 25 and chassis ground. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise, repair the electrical wiring in the area between the battery and the control module/hydraulic modulator. Check the SBF fuse holder.
Turn off the ignition and measure the resistance between ground and terminal No. 26 of connector F49. If the measurement result is less than 0.5 Ohm, proceed to the next step of the test, otherwise, repair the control unit ground circuit.
Run the engine at idle speed and measure the voltage between terminal No. 1 of connector F49 and chassis ground. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the electrical wiring in the areas between the battery, ignition switch and ABS control module. Carry out the necessary restorative repairs.
Turn off the ignition and measure the resistance between ground and terminal No. 23 of connector F49. If the measurement result is less than 0.5 Ohm, proceed to the next stage of testing, otherwise eliminate the cause of the grounding quality problem.
While checking the operating sequence of the hydraulic modulator valves (see Section Checking the actuation sequence of the ABS hydraulic modulator valves) Check by ear that the electric motor is functioning properly. If the motor rotates properly, proceed to the next test step, otherwise replace the ABS modulator/control unit assembly.
Check the condition and reliability of fixation of the electrical wiring contact connectors on the control module/ABS hydraulic modulator assembly, generator and battery. If necessary, make appropriate repairs. If there are no contact quality violations, proceed to the next stage of testing.
Turn off the ignition. Restore the original electrical wiring connections. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no changes (for improvement) have occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, go to the appropriate test. If the failure does not recur, therefore, the malfunction was temporary, once again make sure that all contact connections are securely fastened.
Malfunction of the brake light switch (DTC 54)
Failure of the brake light sensor-switch leads to a malfunction of the ABS.
Check that the brake lights work properly when you depress the foot brake pedal. If everything is in order, proceed to the next step of the test, otherwise check the condition of the lamps and wiring of the brake light circuit.
Turn off the ignition. Disconnect the wiring from the ABS control module. Squeeze the pedal foot brake and measure the voltage between ABS control module connector F49 terminal No. 2 and chassis ground. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the electrical wiring in the area between the brake light sensor-switch and the ABS control module. Carry out the necessary restorative repairs.
Check the condition and reliability of fixation of the contact connectors of the sensor switch and the control unit. If necessary, make appropriate corrections. If the contacts are OK, proceed to the next step of the test.
Malfunction of the G-sensor output signal (DTC 56)
Check the markings of the ABS control module/hydraulic modulator assembly - the code is applied to the surface of the block between the hydraulic line connection fittings and for models (see Specifications). If the marking corresponds to the configuration of your car, proceed to the next step of the test, otherwise replace the ABS control module/hydraulic modulator assembly.
|
Turn off the ignition. Remove the center console (see Chapter Body). Unbolt the G-sensor without disconnecting the electrical wiring from it. |
Turn the ignition key back to the ON position and measure the voltage between terminals No. 1 (+) and 3 (-) on the outside of the sensor connector R70.
Disconnect the wiring from the G-sensor. Measure the resistance between terminal No. 6 of connector F49 and chassis ground. If the measurement result is more than 1 MOhm, proceed to the next step of the test, otherwise make the necessary repairs to the wiring in the area between the sensor and the ABS control module.
Measure the voltage between terminal No. 6 of connector F49 and chassis ground. If the measurement result is less than 1 V, proceed to the next step of the test, otherwise make the necessary repairs to the wiring in the area between the sensor and the ABS control module.
Repeat the last check with the ignition on. If the measurement result is less than 1 V, proceed to the next step of the test, otherwise make the necessary repairs to the electrical wiring in the area between the sensor and the ABS module.
Measure the resistance between ground and terminal No. 28 of connector F49. If the measurement result is more than 1 MOhm, proceed to the next step of the test, otherwise make the necessary repairs to the wiring in the area between the sensor and the ABS control module. If the wiring is OK, replace the control module/hydraulic modulator assembly.
Turn off the ignition and, without disconnecting the electrical wiring, unscrew the G-sensor. Check the secure fit of the contact connectors of the sensor and the ABS control module. Turn on the ignition and measure the voltage between terminals No. 2 (+) and No. 3 (-) of the R70 sensor connector. If the measurement result does not fall outside the range of 2.1 ÷ 2.4 V, proceed to the next test step, otherwise replace the sensor.
Tilt the sensor 90° forward and repeat the above check. If the measurement result does not fall outside the range of 3.7 ÷ 4.1 V, proceed to the next test step, otherwise replace the sensor.
Tilt the sensor 90° back and repeat the test. If the measurement result does not fall outside the range of 0.5 ÷ 0.9 V, proceed to the next test step, otherwise replace the sensor.
Turn off the ignition. Check the condition and tightness of the contact connectors of the G-sensor and the ABS module. If necessary, carry out appropriate repairs. If the contact connections are OK, proceed to the next test step.
Restore the original electrical wiring connections. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no changes (for improvement) have occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, go to the appropriate test. If the failure does not recur, therefore, the malfunction was temporary, once again make sure that all contact connections are securely fastened.
Checking ABS Control Module I/O Signals
Map of the location of the contact terminals in the control module/hydraulic modulator connector and diagram electrical connections ABS components are shown in the illustrations.
ABS wiring diagram
1 - Control module assembly/ABS hydraulic modulator |
13 - Right rear wheel exhaust solenoid valve |
Map of the location of the contact terminals in the ABS control module connector
The shape of the signal taken from the individual terminals of the ABS sensors is shown in Resistance. illustrations. The list of signals is given in the table.
Reading ABS Trouble Codes (DTCs)
For a list of ABS DTCs, see Specifications on this Chapter.
Reading DTCs Using SSM
Prepare the SSM reader for operation.
Connect to SSM diagnostic cable and refill the cartridge.
Connect the SSM diagnostic cable to the DLC connector located on the left under the vehicle's instrument panel.
Turn the ignition key to the ON position (do not start the engine) and turn on the power to the SSM.
In the main menu (“Main Menu”) of the reader screen, select the section (Each System Check) and press the YES key.
In the “System Selection Menu” field of the screen, select the subsection (Brake Control System), confirm the selection by pressing the YES key.
After displaying information about the ABS type, press the YES key again.
In the “ABS Diagnosis” field of the screen, select the item (Diagnostic Code(s) Display) and confirm the selection by pressing the YES key.
In the “Diagnostic Code(s) Display” field of the screen, select (Current Diagnostic Code(s)) or (History Diagnostic Code(s)), press the YES key.
Reading current data
Enter the menu subsection (Brake Control System), wait for the message about the ABS type to appear on the screen and press the YES key.
In the “Brake Control Diagnosis” field of the screen, select the item (Current Data Display & Save) and confirm the selection by pressing the YES key.
In the Data Select Menu field, select (Data Display) and press YES.
Use the scroll buttons to navigate through the list displayed on the screen to select the data you are interested in. The list of output data is given in the table below.
|
Monitor screen |
Output type |
Units |
|
Speed corresponding to the rotation speed of the right front wheel |
Data output from the right front wheel sensor |
km/h or mph |
|
Speed corresponding to the rotation speed of the left front wheel |
Left front wheel sensor data |
km/h or mph |
|
Speed corresponding to the rotation speed of the right rear wheel |
Data output from right rear wheel sensor |
km/h or mph |
|
Speed corresponding to the rotation speed of the left rear wheel |
Data output from left rear wheel sensor |
km/h or mph |
|
Brake light switch |
Sensor-switch status |
On or Off |
|
Brake light switch |
The voltage of the brake light sensor-switch is output | |
|
G-sensor input |
G-sensor signal voltage (vehicle acceleration data) | |
|
Valve relay signal |
Valve relay signal |
On or Off |
|
Motor relay signal |
Motor relay signal |
On or Off |
|
ABS signal to TCM |
Signal issued by the ABS control module to the TCM AT |
On or Off |
|
ABS warning lamp |
Output of data on the operation of the ABS warning lamp |
On or Off |
|
Motor relay monitoring |
Output of data on activation of the electric motor relay |
High or low |
|
Valve relay monitoring |
Valve relay activation output |
On or Off |
|
SSM signal |
ABS operating signal issued by the ABS control module to the AT TCM |
On or Off |
Reading DTCs without SSM
Remove the diagnostic connector located next to the driver's seat heater unit.
Turn off the ignition and connect the diagnostic terminal to terminal No. 8 of the connector.
Turn on the ignition, the ABS warning lamp will go into diagnostic mode and begin flashing fault codes (DTCs) stored in the processor memory.
The check start code (11) is always displayed first, then all other codes are displayed one by one, starting with the last one. After the last code is output, the cycle repeats for 3 minutes. Examples of code output are shown in the illustration. If there are no codes stored in the memory, the control lamp will only display the start code (11).
Removing codes from processor memory
Using SSM
In the main menu (“Main Menu”) of the SSM reader, select the item (2. Each System Check) and press the YES key.
In the System Select Menu field, select (Brake System), press YES, wait for the ABS type information to be displayed, then press YES again.
In the “Brake Control Diagnosis” field of the screen, select the item (Clear Memory) and confirm the selection by pressing the YES key.
Once the reader displays “Done” and “Turn ignition OFF”, remove power from the SSM and turn off the ignition.
Without SSM
Within approximately 12 seconds, repeat the terminal connection/disconnection procedure three times with the duration of each phase (On and Off) of at least 0.2 s.
Successful completion of memory clearing is confirmed by the indicator lamp illuminating code 11.
The ABS system is installed on many modern cars. Toyota Corolla 2007, 2008, and cars of more recent years of production were also equipped with this system. However, motorists often encounter the following problem: the ABS sensor lights up. This means that you need to check the ABS or the sensor itself.
How is ABS used?
The ABC system is necessary to stabilize braking and improve the behavior of wheels on difficult sections of the road: for example, it should be activated during sudden braking on a slippery road or when skidding. The purpose of the ABS unit is to prevent the brakes from locking and the car body from skidding, thus allowing the driver to maintain controllability. It will be possible to press the brake pedal all the way without thinking about the intermittency of this action, which the car will perform itself.
During emergency braking, slippage will not occur, which is why it is important to ensure that the anti-lock braking unit is in good working order.
How does the anti-lock brake system work?
In order to figure out whether the system is working correctly, you need to know how it should operate in good condition. On the Toyota Corolla 120, the system works as follows: as soon as braking begins, sensors installed on the car's wheels monitor the initial braking impulse.
Hydraulic cylinders are controlled through an electrical wire, this helps prevent slippage, since the sensor sends a signal to the system possible blocking brakes Thanks to this, there is a strong grip on the road and no skidding occurs.
On cars without a sensor, the driver must control the situation by removing his foot from the brake pedal and pressing it again, but it is quite difficult to accurately track the moment when the car lost traction, and skidding becomes inevitable.
Why might errors occur?
The Corolla 150 is a reliable car, however Russian conditions operation may affect the sensors not in the best possible way. Most often, if the ABS icon appears on the dashboard, you need to check for faulty ABS sensor.
When you turn on the engine, the light should light up and go out after a certain time: this is a normal reaction of the system to turning on, but if it turns off ABS lamps happens again, this already indicates a malfunction in the control unit or sensor. The notification may light up the following reasons: the fuses have failed, the electrical system wires do not transmit pulses well, the sensor itself is faulty, the control unit has failed, communication with the sensor has been lost.
If the lamp does not light constantly, but flashes frequently, then the problem may be in the operation of the car’s generator.
How to check the fault?
It is best to check the operation of the Toyota Corolla ABS at a specialized car service center, where they can determine exactly what the problem is and fix it. If the car has an on-board computer, the technician will be able to read the error number and understand what is wrong.
However, some manipulations can be done independently.
Without this element the device will not work. You can find the fuse box under the hood: check the fuses, connectors, and replace blown ones if necessary.
The control unit is also located under the hood. You can find the control unit by the tubes coming from the brakes and wires. The control unit can receive mechanical damage, so you need to inspect it visually first. You will first need to remove the electrical wire from it. Check whether water has entered the unit: if it is wet, it needs to be dried.
After washing, a similar problem may also occur, as moisture gets on the wiring. The wet wire shorts out and the wheel sensor cannot communicate with other parts of the system; in this situation you need to wait until the wire dries.
Major repairs may be required if the wheel bearing is faulty. To do this, you need to accelerate the car to at least 80 km/h and listen: if you hear a distinct hum, then the bearing needs to be replaced. Most often the front one breaks, but if, for example, the rear left one requires repair, the bearings are replaced on both sides of the axle. If the rear bearing is faulty, it is not necessary to change the front right or left element.
In the same situation, you can check the brakes. Pay attention to how the car behaves when you press the pedal, whether it skids, whether you feel a blow to it from a working ABS. You will quickly understand if the system is not working. If the ABS sensor does not work, you will need to lift the car on a lift: each wheel has its own sensor, so you need to check them one at a time. The connectors may become oxidized and the sensors themselves may become clogged with dirt. You also need to check the integrity of the wires.
Conclusion
It is possible to use the vehicle when the ABS sign is on, but it is better to have it repaired, as the wheels may lose traction if they hit a slippery surface, which will affect your safety. It is recommended that serious repairs be done in a workshop, but you can determine what the problem is yourself, for which you can use a minimum of tools.
In order to prevent the car's wheels from locking and, as a result, skidding on the road, the Toyota Corolla uses an anti-lock braking system. By appointment completely automated system Anti-locking is to maintain controllability in the event of emergency braking of the car, eliminating its uncontrolled slipping.
Rice. 1. Braking trajectories during braking
Anti-blocking operates according to the following principles:
- at the initial moment of braking, special sensors on the wheels record the initial blocking impulse;
- by means of feedback via an electrical wire, a signal is generated that controls the weakening of the force of the hydraulic cylinders even before the start of slipping, the tires regain traction with the road;
- after spinning the wheel, the maximum braking force is again created in the hydraulic cylinders;
Thanks to the repeated repetition of this simple electro-hydromechanical chain, the braking distance is practically no longer than with continuous blocking, but controllability is completely preserved. This allows you to avoid skidding, moving the car into oncoming traffic or onto the side of the road.
The device of the ABS complex
Main components of the anti-lock system:
- speed sensors of front and rear wheels;
- hydraulic valves of the hydraulic brake system;
- elements of the channel for exchanging information between sensors and hydraulic system valves.
Anti-lock braking is especially important for drivers who do not have much experience, since it is enough to hold the brake pedal to the floor, and the system does the rest. But on sections of the road with a loose surface in the form of gravel, sand or snow, the braking distance turns out to be longer than when braking by completely and continuously blocking the brakes. After all, the tires do not bury themselves in the loose mass, but slide along its surface.
Rice. 2. Installation locations of ABS units in the car
In Fig. Figure 2 shows a diagram of the location of the main components of the auto-locking system in the overall structure of the car.
The arrows indicate the following elements:
- Anti-lock complex drive;
- Control relay;
- Control unit and photodiode for turning on the anti-lock braking system;
- Front wheel speed sensor;
- Speed sensor rotor in the front wheel;
- Speed sensor rotor in the rear wheel;
- Rear wheel speed sensor.
The effect of the anti-lock braking system is to maintain the stability and controllability of the car while optimally reducing the speed. All this happens by monitoring the rotation speed of each wheel and periodically releasing pressure in its brake hydraulic line.
ABS electronic module
The anti-lock control unit is located next to the instrument panel. It includes and processes electrical impulses from wheel speed sensors. After processing the information, the unit sends signals to the cavity valves of the anti-lock drive.
Also, with the help of an electronic module, the performance of the entire complex is constantly monitored and tested. In the event of a malfunction, a light signal flashes on the dashboard, warning the driver about emergency situation. The electronics unit is also capable of generating a fault code and storing it for a service station specialist.
A photodiode signal that flashes from time to time warns the driver that deviations in operating parameters are possible in the complex. In this case, you should check the reliability of the connection of the wires from the sensors to the electronic unit, fuses, filling of the main tank brake cylinder brake fluid.
If after this the warning signals continue to appear, then you should contact a specialized Toyota Corolla repair and maintenance center.
Anti-lock braking system drive for Toyota Corolla
The device includes a hydraulic pump and a multi-cavity housing with four magnetic valves. In the drive cavity of each wheel, the required pressure is created and regulated using its own valve. Signals for opening and closing cavity valves come from wheel rotation sensors.
Photo 1. Block Toyota ABS Corolla Fielder
The block can be seen under the hood of the engine compartment. It is located next to the brake cylinder and is connected to it by metal pipes for the flow of brake fluid.
Wheel speed sensors
These elements are installed on the front wheel knuckles. They are located close to the gear rotors of the external connections of the axle shafts and the back of the wheels with rotors on the wheel hubs are mounted on the brake flaps, constantly sending information in the form electrical impulses into the ABS electronic module.
Rice. 3. Toyota Corolla front wheel speed sensor
Anti-lock system activation signals
The driver learns that the system is activated by a specific twitching of the brake pedal at the moment of braking and by a flashing light on the instrument panel. If the light starts to light continuously, this means a malfunction in the anti-lock braking system. However, there is no need to sound the alarm - after all, in case of malfunctions in ABS system braking works like in all cars without anti-lock.
To disable the anti-lock braking system in some Toyota Corolla models, simply press the brake pedal many times, as if braking intermittently. The complex is put into operation again in the same way.
The Toyota Corolla is equipped with a set of safety systems designed to reduce the likelihood of emergency situation, and in the event of a traffic accident - maximum protection driver and passengers.
ABS - anti-lock braking system. Prevents wheel locking during emergency braking or when braking on slippery roads.
EBD - distribution system braking forces. It is part of the anti-lock braking system.
TRC- traction control system. If the drive wheels slip during acceleration, the system automatically reduces engine torque and brakes the wheel that has slipped, helping to restore traction.
VSC - exchange rate stability system. Automatically triggers when it detects a skid due to sudden steering or insufficient contact with a slippery road. By braking one wheel or another and changing the engine torque, it brings the car out of a skid and helps the driver stabilize the trajectory.
BA - emergency braking assistance system. Provides emergency braking when the driver presses the brake pedal sharply, but not hard enough. To do this, the system measures how quickly and with what force the pedal is pressed, and then, if necessary, instantly increases the pressure in the pedal. brake system to maximum efficiency.
ABS Toyota Corolla
The anti-lock brake system (ABS) consists of wheel speed sensors, a brake pedal switch, a hydroelectronic control module and warning lights in the instrument cluster. The anti-lock braking system includes brake force distribution (EBD) and a self-diagnosis system that detects malfunctions of system components.
ABS serves to regulate the pressure in the brake mechanisms of all wheels when braking in difficult road conditions and thereby prevents wheel locking.
The ABS system provides the following benefits:
Avoiding obstacles with a higher degree of safety, including during emergency braking;
Reducing the braking distance during emergency braking while maintaining directional stability and controllability of the vehicle, 8 including when turning.
In the event of a system malfunction, diagnostic functions and maintenance of operation in the event of system failures are provided.
The hydroelectronic control module receives information about vehicle speed, direction of travel and road conditions from the wheel speed sensors and the position sensor throttle valve. After turning on the ignition, the control unit supplies voltage to the wheel speed sensors. They use the Hall effect and generate an output signal in the form of pulses. The signal changes in proportion to the rotation frequency of the sensor pulse ring.
Based on this information, the control unit determines the optimal wheel braking mode.
There are the following operating modes of the anti-lock braking system:
Normal braking mode. During normal braking inlet valve open, exhaust valve closed. When you press the brake pedal, brake fluid is pressurized into the slave cylinder and operates brake mechanisms wheels When the brake pedal is released, brake fluid returns to the master cylinder through the inlet and check valves;
Emergency braking mode. If a wheel locks during emergency braking, the module sends a command to the pump electric motor to reduce the brake fluid supply, then voltage is applied to each solenoid valve. The inlet valve closes and the supply of brake fluid from the master cylinder and pump is shut off; The exhaust valve opens and brake fluid flows from the working cylinder into the main cylinder and then into the reservoir, which causes a decrease in pressure;
Pressure maintenance mode. When the pressure in the working cylinder decreases to a maximum, the module issues a command to maintain brake fluid pressure; voltage is supplied to the intake valve and not to the exhaust valve. At the same time, the inlet and exhaust valves are closed and the brake fluid does not leave the working cylinder;
Pressure boost mode. If the module determines that the wheel is not blocked, then voltage is not supplied to the solenoid valves, and the brake fluid enters the working cylinder through the inlet valve, the pressure in which increases.
To diagnose and repair the anti-lock brake system, you need special equipment and equipment, so if it fails, contact a specialized service station.
If the anti-lock brake system warning light comes on in the instrument cluster, the diagnostic code can be used to determine the cause of the system malfunction. To check the DTCs, do the following:
1. Pry up the latch...
3. Install a test lamp between the diagnostic connector contacts “4” and “13” to read the anti-lock brake system fault codes.
4. Set the ignition key (lock) to the “ON” position.
5. After 4 s, the indicator lamp will start flashing, for example: flash, pause (approximately 1.5 s), flash, flash, flash (serially at 4 s intervals). By counting the number of flashes before and after the pause, we determine the fault code
If there are two or more faults in the system, the series of flashes are repeated in blocks, in which fault codes are displayed sequentially at 2.5 second intervals, and the blocks are repeated at 4 second intervals. If the control lamp does not light up, check the connections of terminal “4” to ground and terminal “13” to the control unit.
If there are no faults, the warning lamp flashes at intervals of 0.25 s.
6. Set the ignition key to the “ACC” position and disconnect the warning lamp from the diagnostic connector.
7. Set the steering wheel to the straight-ahead position of the vehicle.
8. Install a test lamp between pins “4” and “12” of the diagnostic connector to read the anti-lock brake system fault codes.
9. Set the ignition key to the “ON” position. The warning light should first come on for a few seconds and then start flashing. If the control lamp does not light up, check the connections of terminal “4” to “ground” and terminal “12” to the control unit.
10. Take a test drive while driving the car in a straight line at a speed of at least 45 km/h and no more than 80 km/h. While driving, the warning light should go out.
11. Stop the car - the warning light should flash.
12. Install an additional test lamp between contacts “4” and “13” of the diagnostic connector and perform steps 5.
13. To exit the ABS fault code checking mode, turn off the ignition and remove the warning lamps.
To eliminate fault codes from the control unit memory, do the following.
1. Pry up the latch.
2. ...and open the diagnostic connector cover.
3. Install a test lamp between pins “4” and “13” of the diagnostic connector to read the anti-lock brake system fault codes.
4. Set the ignition key (lock) to the “ON” position.
5. Press the brake pedal at least 8 times within 5 seconds.
6. The control lamp should show the absence of malfunctions, i.e. flash at 0.25 s intervals. Otherwise, repeat the operations in paragraphs. 4 and 5.
7. Turn off the ignition and remove the warning lamp.
REPLACING WHEEL SPEED SENSORS
Toyota Corolla front wheel speed sensor installed in the hole in the steering knuckle of the front suspension and is removed complete with the wiring harness.
Replacement of the sensor on the left front wheel is shown. The sensor on the right front wheel is replaced in the same way.
2. Brake the rear wheels, place them under wheel chocks(“shoes”), loosen the front wheel nuts, lift the front of the car, place it on reliable supports and remove the front wheel.
3. Remove the front wheel arch liner
4. Remove the bolt securing the front wheel speed sensor to the steering knuckle.
5. Remove the sensor from the hole in the fist.
6. Using a screwdriver, open the lower lock and remove the sensor wiring harness
7. Remove the bolt and disconnect the lower mounting bracket for the wiring harness from the front suspension strut.
8. Remove the bolt and disconnect the upper mounting bracket for the wiring harness from the body.
9. Using a screwdriver, open the upper lock and remove the front wheel speed sensor wiring harness.
10. Press out the block fastening clamp, disconnect the wiring harness block and remove the front wheel speed sensor assembly with the wiring harness.
11. Install the front wheel speed sensor and all removed parts in the reverse order of removal.
When installing the front wheel speed sensor, align the hole in the front wheel speed sensor housing with the threaded hole in the knuckle. During installation, do not rotate the sensor around its longitudinal axis. The increase in resistance to movement of the sensor should only be felt the last 2 mm before it is completely seated in the fist. If the sensor enters the knuckle hole with great resistance from the very beginning of installation, remove the sensor and eliminate the cause of the jamming (dirt, burr on the body, etc.)
It is strictly forbidden to press in the wheel speed sensor with a hammer.
You will need: a flat blade screwdriver, 14" and 17" wrenches, a 14" socket with an extension.
Replacement of the sensor on the left rear wheel is shown. The sensor on the right rear wheel is replaced in the same way.
1. Disconnect the wire from the negative terminal of the battery.
2. Engage 1st gear (move the automatic transmission selector to the “P” position), install wheel chocks (“shoes”) under the front wheels, loosen the rear wheel nuts, lift back car, place it on reliable supports and remove the rear wheel.
3. Use a screwdriver to pry off the latch.
4 . .open and remove the housing of the rear wheel speed sensor pad.
5. Disconnect the rear wheel speed sensor wiring harness connector.
6. Remove the brake caliper
7. Remove the brake disc
8. Remove the rear wheel hub
9. Install the rear wheel hub assembly with the speed sensor and all removed parts in the reverse order of removal.
REMOVAL OF THE HYDROELECTRONIC MODULE
: 1 - pipeline of the primary circuit of the main brake cylinder; 2 - pipeline of the second circuit of the main brake cylinder; 3 - pump; 4.5 - bolts securing the module to the bracket; b - bracket for attaching the module to the body; 7 - pipeline of the working brake cylinder of the right front wheel; 8 - pipeline of the working brake cylinder of the left rear wheel; 9 - pipeline of the working brake cylinder of the right rear wheel; 10 - pipeline of the working brake cylinder of the left front wheel; 11 - wiring harness block
The hydroelectronic module for controlling the anti-lock brake system is installed on bracket 6 (Fig. 13.1) in engine compartment on the left and attached to the bracket through rubber pads with bolts 4 and 5.
AND special keys“10”, “14” for loosening pipeline nuts.
1. Disconnect the wire from the negative terminal of the battery.
2. Pump out brake fluid from the brake master cylinder reservoir
3. Unscrew the six fastening nuts and disconnect the hydroelectronic module pipelines.
4. Slide the wiring harness block lock up.
5. Disconnect the wiring harness connector from the hydroelectronic module.
6. Unscrew the two front and one bottom mounting bolts and remove the hydroelectronic module.
7. Install the hydroelectronic anti-lock brake control module and all removed parts in the reverse order of removal.
8. Bleed the brake system
Airbag layout diagram: 1 - driver airbag; 2 - passenger airbag; 3 - side airbags; 4 - curtains
The actual airbags installed in the vehicle may appear different from those shown in the illustration.
The passive safety system (SRS) of the Toyota Corolla, Auris combines front airbags 1 and 2 and side airbags 3 for the driver and passenger. front seat, 4 inflatable side curtains (depending on configuration), height-adjustable seat belts for the driver and front passenger with pretensioners, inertia seat belts for rear passengers, child mounts ISOFIX seats, front seat with WIL rear impact protection system to prevent spinal injuries.
Airbags are not a replacement for seat belts. Moreover, when the car is moving, the driver and front passenger must be wearing seat belts, since in the event of a traffic accident, a deployed airbag itself can cause serious injury to a person who is not wearing a seat belt. In addition, rear seat passengers must wear seat belts. In the event of an accident, an unbelted passenger in the rear seat can cause injury and serious injury to all passengers in the vehicle.
Do not install or place any accessories on the front panel in front of the passenger above glove box in the car. Such objects may move suddenly and cause injury when the passenger airbag inflates.
When installing an air freshener inside the cabin, avoid placing it near instruments or on the surface of the dashboard. Such objects may move suddenly and cause injury when the passenger airbag inflates.
The deployment of airbags may be accompanied by a loud noise and the spread of fine dust throughout the cabin. This is normal since the airbags, when inoperative, are packed in this powder. Dust released during the expansion of pillows can cause irritation to the skin or eyes, and increase the asthmatic reaction of some people. After an accident in which the airbags deploy, thoroughly rinse all open areas skin with warm water and toilet soap.
The SRS airbag system is designed to deploy only when the force of the frontal impact is sufficiently large and its direction makes an angle of no more than 30° with the longitudinal axis of the vehicle. In addition, it is a single use system. Front airbags are not designed to inflate in the event of a side collision, rear impact, or rollover.
Children under the age of 12 must be transported using a special child restraint device. The use of a child restraint system is determined by the Road Traffic Regulations, and its fastening in the vehicle interior is determined by the manufacturer’s recommendations.
It is the driver's responsibility to ensure that the passenger's front airbag switch is positioned correctly. The passenger's front airbag should only be turned off when the ignition is off, otherwise the airbag system control unit may fail.
The SRS system includes the following elements:
The driver's airbag module, located in the steering wheel hub and consisting of a folded airbag shell and an inflator;
Driver's foot airbag module (optional), located at the bottom of the instrument panel;
The front passenger airbag module, located under the instrument panel on the passenger side and consisting of a folded airbag shell and an inflator. Differs from the driver's airbag in shape and larger volume;
The driver and front passenger side airbag modules are located in the outer side parts of the front seat backrests and consist of a folded airbag shell and a gas generator;
Curtain airbag modules for the driver and passengers (in a variant version), located under the facings of the front and rear pillars of the body and consisting of a folded airbag shell and a gas generator.
The airbag locations are indicated by the “SRS AIRBAG” symbol;
Front seat belt pretensioner modules, combined with inertia reels, located in the central pillars of the body, behind the lower pillar trim;
An electronic control unit installed in the instrument panel, under the heating, air conditioning, and interior ventilation control unit.
The ECU contains micromechanical sensors that measure the longitudinal and lateral acceleration of the vehicle during a collision. The ECU estimates the force of the impact by comparing the values it receives from the front impact sensors, side impact and internal electronic sensors, with a given value. If the deceleration signal due to a frontal or side impact exceeds a predetermined value, the computer triggers the activation of the seat belt pretensioners and deployment of the associated airbags.
If your car's battery is damaged during an accident, electrical circuit holding voltage in the ECU will still be able to activate the airbags for some time after the impact;
Frontal and side impact sensors that transmit acceleration information to the system control unit.
The side impact sensors are located on the B-pillar, behind the lower pillar trim.
The strength and direction of impact during a traffic accident is determined by the electronic unit control (ECU) of the passive safety system using shock sensors. Based on sensor signals, the control unit activates airbags and front seat belt tensioners;
Seat belts. When an impact of a certain force occurs, the ECU, having received signals from the impact sensors, increases the tension of the belts before activating the airbags, issuing a command to the pyrotechnic elements of the pretensioners. The latter provide a timely response to emergency deceleration of the car, pulling the driver and front passenger to the backs of the seats, preventing them from further moving forward by inertia and getting injured from a deployed airbag;
Head restraints installed in the backs of all seats prevent damage to the cervical vertebrae of people sitting in the car in the event of a strong rear impact and when the airbags deploy. The front seat head restraints feature WIL technology, which further reduces the risk of neck and spine injuries in rear impacts.
The headrests of the front and rear seats can be adjusted in height by pressing the lock and moving them up or down to the required height
The optimal position of the headrest is one in which its upper edge is located at the same level as the top of the head.
For very tall people, raise the head restraint to its highest position; for very short people, lower the head restraint to its lowest position.
- passive safety system indicators.
The high pressure passive safety system fault indicator (with a red filter) is located on the right side of the instrument cluster. Lights up when the ignition is turned on, stays on for about a minute, and goes off if the system is working properly. If the warning light does not go off (or comes on while driving), it means that there is a malfunction in the passive safety system.
If the warning light comes on, immediately contact a car service center. Besides possible refusal airbags in an emergency, they may unexpectedly deploy while driving, leading to serious consequences.
The airbag deactivation warning lamp A comes on and stays on if the passenger's front airbag is deactivated.
The airbag warning light B comes on and stays on if the passenger's front airbag is activated.
The front passenger seat belt warning light B lights up and flashes when the ignition is switched on if the front passenger seat belt is not fastened. The presence of a front passenger is detected by a special sensor in the front seat.
The driver's seat belt warning light is located on the right side of the instrument cluster; it lights up and flashes when the ignition is on if the driver's seat belt is not fastened;
The front passenger airbag switch is located on the side
The surface of the instrument panel, on the right side. The switch turns off the front passenger airbag when transporting a child in the front passenger seat
Do not unnecessarily deactivate the front passenger airbag unless a child restraint is installed in the front seat.
This subsection describes the removal and installation of driver and front passenger airbags, and the removal and installation of seat belts. Side airbags and curtain airbags should only be removed by a workshop by specially trained personnel.
You will need: a flat-blade screwdriver, a TORX TZO wrench.
1. Disconnect the wire from the negative terminal of the battery.
Before replacing a fuse or disconnecting the battery, turn the ignition key to the “LOCK” position and remove it from the ignition. Never remove or replace fuses related to the airbag system while the ignition key is in the "ON" position. Failure to heed this warning will cause the airbag warning light to illuminate. To turn off the alarm, you will have to contact a specialized auto repair center.
2. Using a screwdriver, press the latches and remove the plugs from the left and right side steering wheel.
3. Using a TORX TZO wrench, remove the screws securing the steering wheel pad on the left and right sides.
4. Pull the airbag cover away from the steering wheel
5. C inside steering wheel pad, disconnect the horn terminal.
6. Using a screwdriver, pull out the lock of the airbag wiring harness...
7. ...disconnect the wiring harness block and remove the airbag.
Do not disassemble the airbag module.
Do not drop the airbag module and do not allow water, grease or oil to come into contact with it.
The airbag module must not be exposed to temperatures above 95 °C
8. Install the driver's airbag and all removed parts in the reverse order of removal.
When installing the module in the steering wheel of a car, be outside the deployment zone of the airbag.
REMOVAL AND INSTALLATION OF FRONT PASSENGER AIR BAG
You will need: flat-blade and Phillips-blade screwdrivers, 10mm wrench.
1. Disconnect the wire from the negative terminal of the battery.
Attempting to remove an airbag module without disconnecting its power supply may result in unexpected deployment of the airbag.
You can begin subsequent operations to remove the airbag only after the activator capacitor has completely discharged. To discharge the capacitor, you must wait at least one minute after turning off the power supply.
2. Remove the top of the instrument panel
3. From the inside of the instrument panel, remove the two screws securing the airbag brackets
4. Disconnect the front and rear holders.
5. ...and remove the airbag.
Do not disassemble the airbag module.
Do not drop the airbag module and do not allow water, grease or oil to come into contact with it.
The airbag module must not be exposed to temperatures above 95°C.
6. Install the front passenger airbag and all removed parts in the reverse order of removal.
When you first turn on the ignition after installing the airbag module in the vehicle, stand outside the vehicle and turn on the ignition switch with your hand under the steering column.
REMOVAL AND INSTALLATION OF THE ELECTRONIC RESTRAINT CONTROL UNIT
You will need: flat and Phillips blade screwdrivers, 10" and 12" wrenches.
For clarity, the work is shown on a car with removed panel devices.
1. Disconnect the wire from the negative terminal of the battery.
After disconnecting the wire from the negative terminal of the battery, you must wait at least a minute, and only then can you disconnect the ECU wiring harness block.
2. Remove the floor tunnel lining
3. On the center console, remove the ashtray unit, the security system display unit, the control unit for the heating, air conditioning and interior ventilation system
4. Overcoming the resistance of the clamps, disconnect the central air duct from the unit of the heating, air conditioning and interior ventilation system and remove the air duct.
5. Press the lever lock and turn the wiring harness block fixing lever to the left
6. Disconnect the ECU wiring harness connector
7. Remove the front ECU mounting bolt
8. Remove the left and right bolts rear mount ECU.
9. Pull towards you and remove the electronic control unit for the passive safety system.
10. Install the passive safety system control unit and all removed parts in the reverse order of removal.
Replacing a Toyota Corolla shock sensor
You will need: flat-blade and Phillips-blade screwdrivers, 10mm wrench.
To replace the side impact sensor, do the following:
1. Disconnect the wire from the negative terminal of the battery.
Replacement of the spruce side side impact sensor is indicated.
The side impact sensor on the right side is replaced in the same way.
2. Remove the lower trim of the B-pillar
3. Slide the wire harness block clamp...
4. ...and disconnect the side impact sensor connector.
5. Remove the bolt securing the sensor to the central pillar of the body.
6. Remove the side impact sensor.
7. Install the side impact sensor and all removed parts in the reverse order of removal.
To replace the front impact sensors, do the following:
1. Disconnect the wire from the negative terminal of the battery.
After disconnecting the wire from the negative terminal of the battery, you must wait at least one minute, and only after that you can begin to remove the sensor.
Frontal impact sensors are located on the side members of the car body in the front part of the engine compartment.
Replacement of the front impact sensor on the left side of the vehicle is shown.
