| Last Modified: 11-29-2007 | 1.6 U | |
| Service Category: Brake | Section: Brake Control/Dynamic Control System | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000001DX000NX |
| Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: FAIL-SAFE CHART (2008 Sequoia) | ||
FAIL-SAFE CHART
1. FAIL SAFE OPERATION
-
If there is a problem with sensor signals or actuator systems, the skid control ECU prohibits power supply to the VSC actuator and informs the ECM of VSC system failure.
The VSC actuator turns off each solenoid and the ECM shuts off VSC control (traction control signal) from the skid control ECU. As a result, it is as if the ABS, TRAC and VSC systems are not installed in the vehicle.
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
. -
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 the termination of the systems
.
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 VSC actuator, brake performance will gradually decrease and control of the ABS, BA, TRAC, A-TRAC, VSC and AUTO LSD systems will be prohibited.
(a) ABS, EBD and BA system:
|
Malfunction Area |
Control Method |
|---|---|
|
ABS system |
ABS, BA, TRAC, A-TRAC, VSC and AUTO LSD control is prohibited |
|
BA system |
ABS, BA, TRAC, A-TRAC, VSC and AUTO LSD control is prohibited |
|
EBD system |
ABS, EBD, BA, TRAC, A-TRAC, VSC and AUTO LSD control is prohibited |
(b) TRAC, A-TRAC, VSC and AUTO LSD system:
HINT:
As for the TRAC, A-TRAC, VSC and AUTO LSD systems, different systems prohibit different controls according to the malfunctioning part.
|
Malfunction Area |
Control Method |
|---|---|
|
Engine control system (TRAC, A-TRAC and VSC 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 engine to effect control |
|
Brake control system (TRAC, A-TRAC and AUTO LSD systems) |
Brake control: Disables control During control: Disables control (by gradually ending control) |
2. 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 brake pads may excessively increase. If the temperature excessively increases, the skid control buzzer will sound intermittently. If the temperature increases even more, the skid control buzzer sounds for 3 seconds intermittently and the indicator light either comes on or blinks.
|
System |
Indicator Condition |
|---|---|
|
TRAC or A-TRAC system |
SLIP indicator light comes on VSC OFF indicator light blinks |
|
AUTO LSD system |
SLIP indicator light comes on VSC OFF indicator light blinks AUTO LSD indicator light stays on |
HINT:
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.
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