Fail-Safe Chart

• If there is a problem with any sensor signals or hydraulic brake booster systems, the skid control ECU prohibits the power supply to the actuator in the hydraulic brake booster and informs the ECM of VSC system failure.

  The hydraulic brake booster turns off solenoids and the ECM shuts off the VSC control (traction control signal) from the skid control ECU accordingly, the result of which is as if the ABS, TRAC and VSC systems were not installed.

  ABS control is prohibited, but EBD control continues as far as possible. If EBD control is impossible, the BRAKE warning light comes on to warn the driver. Refer to DIAGNOSIS SYSTEM .

• If system components have any malfunctions before starting control, the operation stops immediately.

  If system components have any malfunctions during control, the control stops gradually 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 the malfunction in the systems. Refer to DIAGNOSIS SYSTEM .

HINT: 

• If the ABS, BA, TRAC, A-TRAC, VSC, AUTO LSD, or crawl control systems malfunction, the brake system will operate normally without ABS, BA, TRAC, A-TRAC, VSC, AUTO LSD or crawl control system controls.
• If the hydraulic brake booster malfunctions, a gradual loss of brake performance is expected, and ABS, BA, TRAC, A-TRAC, VSC, AUTO LSD and crawl control system controls are prohibited.

1. ABS, EBD and BA systems:

   HINT: 

   If the ABS, BA or EBD system malfunctions, the following controls are prohibited as shown in the table below.

   Malfunction Area	Fail-Safe Operation
   ABS system	ABS, BA, TRAC, A-TRAC, VSC, AUTO LSD and crawl control prohibited
   BA system	ABS, BA, TRAC, A-TRAC, VSC, AUTO LSD and crawl control prohibited
   EBD system	ABS, BA, EBD, TRAC, A-TRAC, VSC, AUTO LSD and crawl control prohibited

2. TRAC, A-TRAC, VSC, AUTO LSD and crawl control systems:

   HINT: 

   If TRAC, A-TRAC, VSC, AUTO LSD and/or crawl control malfunction, the following controls are prohibited as shown in the table below.

   Malfunction Area	Fail-Safe Operation
   Engine control system (TRAC and A-TRAC systems)	Before control: Disables control During control: Uses only brakes to effect control
   Brake control system (VSC system)	Before control: Disables control During control: Uses only brakes to effect control
   Brake control system (TRAC, A-TRAC, AUTO LSD and crawl control systems)	Before control: Disables control During control: Disables control (by gradually ending control)

If the TRAC, A-TRAC, AUTO LSD 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 further, the skid control buzzer sounds for 3 seconds repeatedly and the indicator light either comes on or blinks.