NO.5 BRAKE SYSTEM WARNING LIGHT STAYS ON

BME040343000209

• 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.

5

BRAKE system warning light stays ON

[TROUBLESHOOTING HINTS]

• Warning light circuit open in ABS HU/CM

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

Diagnostic procedure

STEP

INSPECTION

ACTION

1
• Is brake fluid level okay?
Yes
Go to next step.
No
Add brake fluid.
2
• Inspect the following items using WDS or equivalent.
- BRAKE_LMP (BRAKE system warning light)
• Is error message displayed regarding communication between ABS HU/CM and WDS or equivalent?
Yes
If a communication error message is displayed even after inspecting according to procedures displayed on the WDS or equivalent, go to Step 5.
No
Go to next step.
3
• Inspect the following items using WDS or equivalent.
- BRAKE_LMP (BRAKE system warning light)
• Is BRAKE_LMP on after more than 4 seconds with ignition switch ON?
Yes
Replace ABS HU/CM (short to B+ in ABS HU/CM).
No
Go to next step.
4
• Disconnect the following connectors in order:
- Parking brake switch connector
- 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.
• If above inspections are okay, replace instrument cluster (open or ground to short in instrument cluster).
*5
• Disconnect ABS HU/CM connector. Connect SST (adapter harness) (vehicle harness side only).
• Is there continuity between SST (adapter harness) connector terminal T and DLC-2)?
Yes
Go to next step.
No
Repair wiring harness between ABS HU/CM and DLC-2.
*6
• Is voltage approximately 12 V at SST (adapter harness) connector terminal T?
Yes
Repair wiring harness between ABS HU/CM and DLC-2.
No
Go to next step.
*7
• Is there continuity between SST (adapter harness) connector terminal T and ground?
Yes
Repair wiring harness between ABS HU/CM and DLC-2.
No
Inspect and repair wiring harness for ABS HU/CM power supply (terminal Z) and ground 1 (terminal AA)).