NO.8 BRAKE SYSTEM WARNING LIGHT STAYS ON MORE THAN 4 s WITH IGNITION SWITCH ON


id040300901800

8

BRAKE system warning light stays on more than 4 s with ignition switch on. (Parking brake is released.)

[TROUBLESHOOTING HINTS]

• Malfunction of instrument cluster or ABS (ABS/TCS) HU/CM

• Short to ground in circuit in parking brake switch and/or brake fluid level sensor

Diagnostic procedure

1
INSPECT BRAKE FLUID LEVEL
Is brake fluid level normal?
Yes
Go to next step.
No
Add brake fluid.

*2

INSPECT WIRING HARNESS BETWEEN ABS (ABS/TCS) HU/CM AND DLC-2 FOR CONTINUITY AND SHORTS
Inspect the following items using WDS or equivalent PID/DATA monitor function.
• BRAKE_LMP (BRAKE system warning light)
Is error message displayed regarding communication between ABS (ABS/TCS) HU/CM and WDS or equivalent?
Yes
If a communication error message is displayed even after inspecting according to procedures displayed on WDS or equivalent.
Go to next step.
No
Go to next step.
3
INSPECT FOR DTCS IN ABS (ABS/TCS) HU/CM
Have DTCs been recorded in memory?
Yes
Perform inspection using appropriate DTC.
No
Go to next step.
4
INSPECT PID/DATA IN ABS (ABS/TCS) HU/CM
Inspect (BRAKE system warning light) using WDS or equivalent PID/DATA monitor function.
Is BRAKE_LMP on after more than 4 s with ignition switch on?
Yes
Connect ABS (ABS/TCS) HU/CM connector terminal O, R securely, then go to next step.
No
Go to step 6.
5
VERIFY WHETHER MALFUNCTION IS IN PARKING BRAKE SWITCH OR BRAKE FLUID LEVEL SENSOR, OR IN SOME OTHER PART
Disconnect the following in order:
1. Parking brake switch connector
2. Brake fluid level sensor connector
Does BRAKE system warning light go out with ignition switch on?
Yes
Replace parking brake switch and/or brake fluid level sensor (shorted on some internal part).
No
Perform the following inspections. Repair if necessary.
• Open in wiring harness between ABS HU/CM (terminal X) and instrument cluster (BRAKE system warning light)
• Short to ground in wiring harness between instrument cluster (BRAKE system warning light) and parking brake switch.
• Short to ground in wiring harness between instrument cluster (BRAKE system warning light) and brake fluid level sensor.
Inspect instrument cluster.

*6

INSPECT WIRING HARNESS BETWEEN ABS HU/CM AND DLC-2 FOR CONTINUITY
Disconnect ABS HU/CM connector.
Is there continuity between connector terminal O, R and DLC-2?
Yes
Go to next step.
No
Repair wiring harness between ABS (ABS/TCS) HU/CM and DLC-2.

*7

INSPECT WIRING HARNESS BETWEEN ABS HU/CM AND DLC-2 FOR SHORT TO B+
Is voltage approx. 12 V at connector terminal O, R?
Yes
Repair wiring harness between ABS (ABS/TCS) HU/CM and DLC-2.
No
Go to next step.

*8

INSPECT WIRING HARNESS BETWEEN ABS HU/CM AND DLC-2 FOR SHORT TO GROUND
Is there continuity between connector terminal O, R and ground?
Yes
Repair wiring harness between ABS (ABS/TCS) HU/CM and DLC-2.
No
Replace ABS (ABS/TCS) HU/CM (communication circuit malfunction in ABS (ABS/TCS) HU/CM).

• When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while doing the inspection to discover whether poor contact points are the cause of any intermittent malfunctions. If there is a problem, check to make sure connectors, terminals and wiring harness are connected correctly and undamaged.