| Last Modified: 11-27-2007 | 1.6 U | |
| Service Category: Brake | Section: Brake Control/Dynamic Control System | |
| Model Year: 2008 | Model: LX570 | Doc ID: RM000001DX000OX |
| Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: FAIL-SAFE CHART (2008 LX570) | ||
FAIL-SAFE CHART
1. FAIL-SAFE OPERATION
-
If there is a problem with sensor signals or hydraulic brake booster systems, the skid control ECU prohibits power supply to the hydraulic brake booster and informs the ECM of VSC system failure.
The hydraulic brake booster turns off each solenoid and the ECM shuts off VSC control (traction control signal) from the skid control ECU accordingly, which turns out to be as if the Multi-terrain ABS, A-TRAC and VSC systems were not installed.
The Multi-terrain 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, the fail-safe function immediately stops the operation.
If system components have any malfunction during control, the fail-safe function gradually stops 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 termination of the systems
.
HINT:
If the hydraulic brake booster encounters a malfunction, brake performance is gradually lost and Multi-terrain ABS, BA, A-TRAC, VSC, CRAWL and hill-start assist control system control is prohibited.
(a) Multi-terrain ABS, EBD and BA system:
|
Malfunction Area |
Control Method |
|---|---|
|
Multi-terrain ABS system |
Multi-terrain ABS, BA, A-TRAC, VSC, CRAWL and hill-start assist control prohibited |
|
BA system |
Multi-terrain ABS, BA, A-TRAC, VSC, CRAWL and hill-start assist control prohibited |
|
EBD system |
Multi-terrain ABS, EBD, BA, A-TRAC, VSC, CRAWL and hill-start assist control prohibited |
(b) A-TRAC, VSC, CRAWL and hill-start assist control system:
HINT:
As for the A-TRAC, VSC, CRAWL and hill-start assist control systems, different systems prohibit different controls according to the malfunctioning part.
|
Malfunction Area |
Control Method |
|---|---|
|
Engine control system (A-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 (A-TRAC, CRAWL and hill-start assist control systems) |
Before control: Disables control During control: Disables control (by gradually ending control) |
2. SYSTEM TEMPERATURE PROTECTION OPERATION
If the A-TRAC, CRAWL, or hill-start assist control system has been used constantly for a long time, the temperature of the hydraulic brake booster 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 and the indicator light either comes on or blinks.
|
System |
Indicator Condition |
|---|---|
|
A-TRAC, and hill-start assist control systems |
Slip indicator light comes on. |
|
CRAWL control system |
Slip indicator light comes on. CRAWL indicator light blinks and then turns off. |
HINT:
- If the slip indicator light goes off (as for the CRAWL control system, the CRAWL control indicator light also comes on), the systems automatically return to normal operating conditions.
- When the CRAWL indicator light turns off after blinking, CRAWL control temporarily becomes nonfunctional, but after the temperature of the hydraulic brake booster drops, CRAWL control becomes operational.
- As this is not a malfunction, no DTC will be stored.
|
|