Toyota Yaris: Vehicle Stability Control System / TRC does not Operate
DESCRIPTION
When TRC or VSC is operating, the skid control ECU (brake actuator assembly) blinks the slip indicator light to inform the driver that slippage occurred.
When in VSC off mode, or TRC and VSC are disabled, the multi-information display in the combination meter assembly displays TRC OFF message and the VSC OFF indicator light illuminates to inform the driver.
When a communication malfunction with the ECM is detected, TRC and VSC are disabled. Also when the system is malfunctioning, TRC and VSC are disabled and the indicator lights of related systems illuminate.
CAUTION / NOTICE / HINT
NOTICE:
After replacing the skid control ECU (brake actuator assembly), perform "Calibration".
Click here
PROCEDURE
(a) Check if the slip indicator light was illuminated when TRC did not operate.
OK:
The slip indicator light was illuminated.
HINT:
When a DTC is stored, the slip indicator light is illuminated and TRC does not operate due to the fail-safe function.
(b) Check the operation condition of the VSC OFF switch (combination switch assembly) when TRC did not operate.
OK:
The VSC OFF switch (combination switch assembly) had been operated to turn off TRC when TRC did not operate.
HINT:
When the multi-information display in the combination meter assembly displays TRC OFF message, TRC does not operate.
OK |
| END |
NG |
| |
(a) Operate the GTS to read the DTCs.
Chassis > Brake > Trouble Codes
(b) Check the DTCs that are output.
OK:
DTCs are not output.
(c) Operate the VSC OFF switch (combination switch assembly) and check that the multi-information display in the combination meter assembly displays TRC OFF message and the VSC OFF indicator light illuminates in accordance with the operation of the switch.
OK:
The multi-information display in the combination meter assembly displays TRC OFF message and the VSC OFF indicator light illuminates in accordance with the operation of the switch.
NG |
| INSPECT COMBINATION SWITCH ASSEMBLY |
OK |
| |
3. | PERFORM DEALER MODE (SIGNAL CHECK) INSPECTION (SPEED SENSOR CHECK) |
(a) Using the GTS, perform a Dealer Mode (Signal Check) inspection sensor check and check that speed sensor Dealer Mode (Signal Check) inspection items change from incomplete to complete.
Chassis > Brake > Utility
Tester Display |
Signal Check |
OK:
Speed sensor Dealer Mode (Signal Check) inspection items change from incomplete to complete.
NG |
| INSPECT AND REPAIR MALFUNCTIONING SPEED SENSOR CIRCUIT |
OK |
| |
4. | PERFORM OPERATION CHECK DRIVING |
(a) Operate the VSC OFF switch (combination switch assembly) and check that the system is not in TRC off mode or VSC off mode.
(b) Check that no DTCs are output and that each warning light is not illuminated.
(c) Start off the vehicle on a low friction surface and check that TRC operates when attempting to make the drive wheels slip.
OK:
TRC operates when slip occurs when starting off.
NOTICE:
-
Even when the system is normal, VSC may not operate when the vehicle speed is low or TRC may not operate due to a malfunction. Make sure that only the drive wheels slip during the procedure.
-
When confirming that the slip indicator light blinks, do not slip the drive wheels longer than necessary. Whether TRC operated or not can be checked by reading the Vehicle Control History (RoB) when the system operated.
Click here
-
Pay attention to your surroundings when performing the procedure and depress the accelerator pedal with caution.
OK |
| USE SIMULATION METHOD TO CHECK |
NG |
| REPLACE BRAKE ACTUATOR ASSEMBLY |
DESCRIPTION Code Tester Display Measurement Item Trouble Area RoB Output from X20D7 Zero Point Calibration of Steering Angle Sensor Malfunction History of the steering angle sensor zero point calibration position differing from the stored value
Poor adjustment of the center position of the steering wheel
Poor adjustment of wheel alignment
Brake CAUTION / NOTICE / HINT NOTICE: After performing the inspection, check and clear the vehicle control history (RoB)...
DESCRIPTION Code Tester Display Measurement Item Trouble Area RoB Output from X20D8 Zero Point Calibration of Steering Angle Sensor Not Acquired History of being unable to obtain the steering angle zero point
Sensor installation
Yaw rate and acceleration sensor (airbag sensor assembly)
Brake CAUTION / NOTICE / HINT NOTICE:
This Vehicle Control History (RoB) may be output during situations when the steering angle sensor zero point calibration temporarily cannot be acquired, such as when the stop light is stuck ON...
Other information:
The window opens while the switch is pressed and it closes while the
switch is pulled up with the ignition switched ON. Do not open or close
three or more windows at the same time.
The front passenger’s side and rear windows can be opened/closed
when the power window lock switch on the driver’s door is in the
unlock position...
TERMINALS OF ECU CHECK STEREO COMPONENT EQUALIZER ASSEMBLY
Terminal No. (Symbol) Terminal Description Condition Specified Condition O131-15(+B) - O131-30(GND) Power source Always 11 to 14 V O131-29(IGP) - O131-30(GND) Power source (IG) Ignition switch ON 11 to 14 V O131-14(ACC) - O131-30(GND) Power source (ACC) Ignition switch ACC 11 to 14 V O131-30(GND) - Body ground Ground Always Below 1 Ω O132-1(MC1+) - O131-30(GND) Active noise control microphone input signal Active noise control microphone LH tapped with finger Pulse generation O132-5(MC1-) - O131-30(GND) Active noise control microphone input signal Always Below 1 Ω O132-2(MC2+) - O131-30(GND) Active noise control microphone input signal Active noise control microphone RH tapped with finger Pulse generation O132-6(MC2-) - O131-30(GND) Active noise control microphone input signal Always Below 1 Ω O131-3(NEI) - O131-30(GND) Engine pulse signal Idling with warm engine Pulse generation (See waveform 1) O131-24(FLI-) Active noise control microphone output signal - - O131-9(FLI+) Active noise control microphone output signal - - O131-23(FRI-) Active noise control microphone output signal - - O131-8(FRI+) Active noise control microphone output signal - - O131-5(RRI+) Active noise control microphone output signal - - O131-20(RRI-) Active noise control microphone output signal - - O131-6(RLI+) Active noise control microphone output signal - - O131-21(RLI-) Active noise control microphone output signal - - O131-7(ASG1) Shield ground - - O131-22(ASG2) Shield ground - - O131-12(FR+) - O131-30(GND) Sound signal Active noise control system operating Pulse generation O131-27(FR-) - O131-30(GND) Sound signal Active noise control system operating Pulse generation O131-13(FL+) - O131-30(GND) Sound signal Active noise control system operating Pulse generation O131-28(FL-) - O131-30(GND) Sound signal Active noise control system operating Pulse generation O131-10(RR+) - O131-30(GND) Sound signal Active noise control system operating Pulse generation O131+25(RR-) - O131-30(GND) Sound signal Active noise control system operating Pulse generation O131-11(RL+) - O131-30(GND) Sound signal Active noise control system operating Pulse generation O131-28(RL-) - O131-30(GND) Sound signal Active noise control system operating Pulse generation O131-1(CANH) CAN communication signal - - O131-16(CANL) CAN communication signal - - (a) Waveform 1 HINT: The oscilloscope waveform shown in the illustration is an example for reference only...