VEHICLE STABILITY CONTROL SYSTEM 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 from being supplied to the hydraulic brake booster and informs the ECM of VSC system failure.
The hydraulic brake booster turns off each solenoid and the ECM stops its VSC (traction control signal), which is based on signals from the skid control ECU. As a result, it is as if the ABS, TRC and VSC systems are not installed in the vehicle.
ABS control is prohibited, but EBD control continues to the extent that it is possible. If EBD control is impossible, the brake warning light comes on to warn the driver (Click here).
If a system component has any malfunction before control begins, operation is prohibited. If a system component has any malfunction during control, the system will gradually stop operating so as not to trigger a sudden change in vehicle conditions.
If it is impossible to control the systems, the indicator lights come on or blink to inform the driver of termination of control of the systems (Click here).
VSC control continues as much as possible while the TRC OFF indicator light is on even when the engine has failed.
Tip:If the hydraulic brake booster encounters a malfunction, brake performance is gradually lost and ABS, BA, TRC, A-TRC, VSC, downhill assist control, hill-start assist control, crawl control and multi-terrain select controls are prohibited.
ABS, EBD and BA system:
Malfunction Area
Control Method
ABS
ABS, BA, TRC, A-TRC, VSC, downhill assist, hill-start assist, crawl and multi-terrain select control are prohibited.
BA system
ABS, BA, TRC, A-TRC, VSC, downhill assist, hill-start assist, crawl and multi-terrain select control are prohibited.
EBD system
ABS, BA, EBD, TRC, A-TRC, VSC, downhill assist, hill-start assist, crawl and multi-terrain select control are prohibited.
TRC, A-TRC, VSC, downhill assist control, hill-start assist control and crawl control system:
Tip:The TRC, A-TRC, VSC, downhill assist control, hill-start assist control and crawl control systems each prohibit different controls depending on the malfunctioning part.
Malfunction Area
Control Method
Engine control system
Before control starts: Control is disabled.
During control: Control is disabled (VSC is enabled).
Brake control system
(VSC system)
Before control starts: Control is disabled.
During control: Control is disabled.
Brake control system
(TRC, A-TRC, downhill assist control, hill-start assist control and crawl control systems)
Before control starts: Control is disabled.
During control: Control is gradually disabled.
SYSTEM TEMPERATURE PROTECTION OPERATION
If the TRC, A-TRC, downhill assist control, hill-start assist control or crawl control system has been used constantly for a long time, the temperature of the hydraulic brake booster may increase excessively. If the temperature increase excessively, the buzzer sounds intermittently. If the temperature increases even more, the buzzer sounds for 3 seconds and the TRC OFF indicator light comes on.
System
Indicator Condition
TRC, A-TRC or hill-start assist control
The TRC OFF indicator light comes on.
Downhill assist control
The TRC OFF indicator light comes on.
The downhill assist control indicator light blinks and then turns off.
Crawl control
The TRC OFF indicator light comes on.
The crawl indicator light blinks and then turns off.
Tip:If the systems automatically return to normal operating conditions, the TRC OFF indicator light goes off. As this is not a malfunction, no DTC is stored.