Fail-Safe Chart

• 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, TRAC 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. Refer to DIAGNOSIS SYSTEM .

• 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. Refer to DIAGNOSIS SYSTEM .

HINT: 

If the hydraulic brake booster encounters a malfunction, brake performance is gradually lost and ABS, BA, TRAC, A-TRAC, AUTO LSD, VSC, downhill assist control, hill-start assist control, crawl control and multi-terrain select control system controls are prohibited.

1. ABS, EBD and BA system:

   Malfunction Area	Control Method
   ABS	ABS, BA, TRAC, A-TRAC, AUTO LSD, VSC, downhill assist, hill-start assist, crawl and multi-terrain select control are prohibited
   BA system	ABS, BA, TRAC, A-TRAC, AUTO LSD, VSC, downhill assist, hill-start assist, crawl and multi-terrain select control are prohibited
   EBD system	ABS, BA, EBD, TRAC, A-TRAC, AUTO LSD, VSC, downhill assist, hill-start assist, crawl and multi-terrain select control are prohibited

2. TRAC, A-TRAC, VSC, AUTO LSD, downhill assist control, hill-start assist control and crawl control system:

   HINT: 

   The TRAC, A-TRAC, VSC, AUTO LSD, 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 (TRAC and VSC systems)	Before control: Disables control During control: Uses only brakes to perform control
   Brake control system (VSC system)	Before control: Disables control During control: Uses only engine to perform control
   Brake control system (TRAC, A-TRAC, AUTO LSD, downhill assist control, hill-start assist control and crawl control systems)	Before control: Disables control During control: Disables control (by gradually ending control)

If the TRAC, A-TRAC, AUTO LSD, 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 increases excessively, the skid control buzzer sounds intermittently. If the temperature increases even more, the skid control buzzer sounds for 3 seconds and the TRAC OFF indicator light comes on.

HINT: 

If the systems automatically return to normal operating conditions, the TRAC OFF indicator light goes off. As this is not a malfunction, no DTC is stored.