Toyota 4Runner: Fail-safe Chart
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 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 (See page
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).
- 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 (See page
).
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.
(a) 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 |
(b) 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) |
2. SYSTEM TEMPERATURE PROTECTION OPERATION
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.
|
System |
Indicator Condition |
|---|---|
|
TRAC, A-TRAC, AUTO LSD or hill-start assist control |
TRAC OFF indicator light comes on |
|
AUTO LSD |
TRAC OFF indicator light comes on AUTO LSD indicator light goes off |
|
Downhill assist control |
TRAC OFF indicator light comes on Downhill assist control indicator light blinks and then turns off |
|
Crawl control |
TRAC OFF indicator light comes on Crawl indicator light blinks and then turns off |
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.
Data List / Active Test
DATA LIST / ACTIVE TEST
1. DATA LIST
HINT:
Using the Techstream to read the Data List allows the values or states of switches,
sensors, actuators and other items to be read without removing any p ...
ABS Control System Malfunction (43)
DESCRIPTION
This DTC is output when the VSC system detects a malfunction in the ABS.
DTC Code
DTC Detection Condition
Trouble Area
43
A m ...
Other materials about Toyota 4Runner:
System Description
SYSTEM DESCRIPTION
1. SYSTEM DESCRIPTION
(a) The Electronic Controlled Automatic Transmission (ECT) is an automatic transmission
that electronically controls shift timing using the Engine Control Module (ECM).
The ECM detects electrical signals that indi ...
Wheels
If a wheel is bent, cracked or heavily corroded, it should be replaced.
Otherwise, the tire may separate from the wheel or cause a loss of handling
control.
Wheel selection
When replacing wheels, care should be taken to ensure that they are
equivalent ...
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