Toyota Yaris: Vehicle Stability Control System / Diagnosis System
DIAGNOSIS SYSTEM
DESCRIPTION
When troubleshooting a vehicle with the diagnosis system, the only difference from the usual troubleshooting procedure is connecting the GTS to the vehicle and reading various data output from the vehicle's skid control ECU (brake actuator assembly).
The skid control ECU (brake actuator assembly) records DTCs when the ECU detects a malfunction in the ECU itself or in its circuits.
To check the DTCs, connect the GTS to the DLC3 on the vehicle. The GTS enables you to clear the DTCs, activate the various actuators, and check the Freeze Frame Data and Data List.
(a) Check the auxiliary battery voltage.
Standard voltage:
11 to 14 V
If the voltage is below 11 V, recharge the auxiliary battery before proceeding to the next step.
(b) Check the DLC3.
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DIAGNOSIS
(a) If a malfunction occurs in one part of the system, the skid control ECU (brake actuator assembly) illuminates the warning light corresponding to the malfunctioning system (ABS warning light, brake system warning light or slip indicator light).
(b) The DTCs are simultaneously stored in memory. The DTCs can be read by connecting the GTS.
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(c) This system has a Dealer Mode (Signal Check) function.
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WARNING LIGHT AND INDICATOR LIGHT INITIAL CHECK
(a) When the ignition switch is turned to ON, check that the ABS warning light, brake system warning light, VSC OFF indicator light and slip indicator light come on for approximately 3 seconds.
HINT:
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When the brake fluid level is low, the brake system warning light comes on.
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If a light does not illuminate, check the communication line between the combination meter assembly and skid control ECU (brake actuator assembly).
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If the ABS warning light or slip indicator light remains illuminated after approximately 3 seconds check for DTCs and check the corresponding code. If no DTC is output, check the communication line between the combination meter assembly and skid control ECU (brake actuator assembly).
| Trouble Area | See procedure |
| ABS warning light circuit (Remains on) |
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| ABS warning light circuit (Does not come on) |
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| Brake warning light circuit (Remains on) |
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| Brake warning light circuit (Does not come on) |
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| VSC OFF indicator light circuit (Remains on) |
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| VSC OFF indicator light circuit (Does not come on) |
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| Slip indicator light circuit (Remains on) |
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| Slip indicator light circuit (Does not come on) |
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PROBLEM SYMPTOMS TABLE If there are no DTCs output and the problem still occurs, check the suspected areas for each problem symptom in the order given in the following table and proceed to the relevant troubleshooting page...
TERMINALS OF ECU TERMINALS OF ECU
*a Component without harness connected (Skid Control ECU [Brake Actuator Assembly]) - - Terminal No...
Other information:
DESCRIPTION When the vehicle is being driven, depressing the accelerator pedal sensor assembly and brake pedal will activate the brake override system to restrict engine output. The conditions for activating the brake override system as well as the items that are controlled are explained below...
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...