Fail-Safe Chart
- FAIL SAFE OPERATION
- If there is a problem with sensor signals or hydraulic brake booster systems, the skid control ECU prohibits power supply to the actuator in the hydraulic brake booster and informs the ECM of VSC system failure.
The hydraulic brake booster turns off each solenoid and the ECM shuts off VSC control (traction control signal) from the skid control ECU accordingly, which turns out to be as if the ABS, TRAC and VSC systems were not installed.
The ABS control will be prohibited, but EBD control continues as much as possible. If EBD control is impossible, the BRAKE warning light comes on to warn the driver (see DIAGNOSIS SYSTEM ).
- If system components have any malfunction before starting control, immediately stop the operation. If system components have any malfunction during control, gradually stop the control so as not to trigger a sudden change in vehicle conditions.
If it is impossible to control the systems, the warning light comes on to inform the driver of termination of the systems (see DIAGNOSIS SYSTEM ).
HINT:
- If the ABS, BA, TRAC, A-TRAC, VSC and AUTO LSD systems encounter a malfunction, the brake system will operate normally without ABS, BA, TRAC, A-TRAC, VSC and AUTO LSD control.
- If there is a problem with the hydraulic brake booster, brake performance will gradually decrease and control of the ABS, BA, TRAC, A-TRAC, VSC, and AUTO LSD systems will be prohibited.
ABS & EBD & BA system:
HINT:
A malfunction in either the ABS or BA system will result in an identical operation, with ABS, BA, TRAC, A-TRAC, VSC and AUTO LSD system control prohibited.
MALFUNCTION AREA AND CONTROL METHOD ABS & EBD & BA SYSTEMMalfunction Area Control Method ABS system ABS, BA, TRAC, A-TRAC, VSC and AUTO LSD control prohibited BA system ABS, BA, TRAC, A-TRAC, VSC and AUTO LSD control prohibited EBD system ABS, EBD, BA, TRAC, A-TRAC, VSC and AUTO LSD control prohibited TRAC & A-TRAC & VSC & AUTO LSD system:
HINT:
As for the TRAC, A-TRAC, VSC and AUTO LSD systems, different systems prohibit different controls according to a malfunctioning part.
MALFUNCTION AREA AND CONTROL METHOD TRAC & A-TRAC & VSC & AUTO LSD SYSTEMMalfunction Area Control Method Engine control system (TRAC, A-TRAC and VSC systems) Before control: Disables control
During control: Uses only the brakes to effect controlBrake control system (VSC system) Before control: Disables control
During control: Uses only the engine to effect controlBrake control system (TRAC, A-TRAC and AUTO LSD systems) Before control: Disables control
During control: Disables control (by gradually ending control) - If there is a problem with sensor signals or hydraulic brake booster systems, the skid control ECU prohibits power supply to the actuator in the hydraulic brake booster and informs the ECM of VSC system failure.
- SYSTEM TEMPERATURE PROTECTION OPERATION
If the TRAC, A-TRAC, or AUTO LSD system has been used constantly for a long time, the temperature of the hydraulic brake booster may excessively increase. If the temperature excessively increases, the skid control (VSC warning) buzzer will sound intermittently. If the temperature increases more, the skid control (VSC warning) buzzer sounds for 3 seconds intermittently and the indicator light either comes on or blinks.
SYSTEM INDICATOR CONDITIONSystem Indicator Condition TRAC or A-TRAC system SLIP indicator light comes on AUTO LSD system SLIP indicator light comes on
AUTO LSD indicator light stays onHINT:
- If the SLIP indicator light goes off, the systems automatically return to normal operating conditions.
- As this is not a malfunction, no DTC will be recorded.