Vehicle Stability Control System (For Hydraulic Brake Booster) Fail-Safe Chart

  1. FAIL-SAFE OPERATION

  1. SYSTEM TEMPERATURE PROTECTION OPERATION

Vehicle Stability Control System (For Hydraulic Brake Booster) -- Fail-Safe Chart



FAIL-SAFE OPERATION
  1. 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 (LandCruiser RM000001DWV046X.html).
  2. If system components have any malfunction before starting control, immediately stop the operation.
    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 (LandCruiser RM000001DWV046X.html).
HINT:
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.

  1. ABS, EBD system 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

  2. TRC, A-TRC, VSC, downhill assist control, hill-start assist control and crawl control system:

    HINT:
    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
    (TRC 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
    (TRC, A-TRC, downhill assist control, hill-start assist control and crawl control systems)
    		Before control: Disables control
    During control: Disables control (by gradually ending control)

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 increases excessively, the skid control buzzer sounds intermittently. If the temperature increases even more, the skid control buzzer sounds for 3 seconds and the TRC OFF indicator light comes on.

System
Indicator Condition
TRC, A-TRC or hill-start assist control
TRC OFF indicator light comes on
Downhill assist control
TRC OFF indicator light comes on
Downhill assist control indicator light blinks and then turns off
Crawl control
TRC OFF indicator light comes on
Crawl indicator light blinks and then turns off
HINT:
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.