NO.3 BRAKE SYSTEM WARNING LIGHT STAYS ON MORE THAN 4 SECONDS WITH IGNITION SWITCH ON. (PARKING BRAKE IS RELEASED.)

BME040343000218

3

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

[TROUBLESHOOTING HINTS]

• ABS/TCS HU/CM detects ABS system malfunction.

• ABS/TCS HU/CM detects low voltage in power supply. (ABS/TCS HU/CM ignition Terminal Z voltage is below about 10 V).

• BRAKE system warning light circuit open or shorted to ground.

• Brake fluid level sensor circuit shorted ground.

Diagnostic procedure

STEP

INSPECTION

ACTION

1
INSPECT ABS WARNING LIGHT
• Does ABS warning light also illuminate?
Yes
Go to symptom troubleshooting No.1.
No
Go to next step.
2
INSPECT BRAKE FLUID LEVEL
• Is brake fluid level okay?
Yes
Go to next step.
No
Add brake fluid.
3
INSPECT WIRING HARNESS BETWEEN ABS/TCS HU/CM AND DLC-2 (DATA KINK CONNECTOR-2) FOR CONTINUITY AND SHORTS
• Inspect the following items using WDS or equivalent.
- BRAKE_LMP (BRAKE system warning light)
• Is error message displayed regarding communication between ABS/TCS HU/CM and WDS or equivalent?
Yes
If communication error message is displayed even after inspecting according to procedures displayed on the WDS or equivalent, go to Step 6.
No
Go to next step.
4
INSPECT PID/DATA IN ABS/TCS HU/CM
• Select the following items using WDS or equivalent?
- BRAKE_LMP (BRAKE system warning light)
• Is BRAKE_LMP is ON after more than 4 seconds with ignition switch ON?
Yes
Replace ABS/TCS HU/CM.
No
Go to next step.
5
VERIFY WHETHER MALFUNCTION IS IN BRAKE FLUID LEVEL SENSOR OR IN SOME OTHER PART
• Disconnect brake fluid level sensor connector.
• Does BRAKE system warning light go out with ignition switch ON?
Yes
Inspect brake fluid level sensor.
No
Perform the following inspections. Repair if necessary.
• Open in wiring harness between ABS/TCS HU/CM (terminal X) and instrument cluster (BRAKE system warning light)
• Short to ground in wiring harness between instrument cluster (BRAKE system warning light)
If above inspections are okay, replace instrument cluster (open or ground to short in instrument cluster).
*6
INSPECT WIRING HARNESS BETWEEN ABS/TCS HU/CM AND DLC-2 FOR CONTINUITY
• Disconnect ABS/TCS HU/CM connector. Connect SST (adapter harness) (vehicle harness side only).
• Is there continuity between SST connector terminal T and DLC-2?
Yes
Go to next step.
No
Repair wiring harness between ABS/TCS HU/CM and DLC-2.
*7
INSPECT WIRING HARNESS BETWEEN ABS/TCS HU/CM AND DLC-2 FOR SHORT TO B+
• Is voltage approximately 12 V at SST connector terminal T?
Yes
Repair wiring harness between ABS/TCS HU/CM and DLC-2.
No
Go to next step.
*8
INSPECT WIRING HARNESS BETWEEN ABS/TCS HU/CM AND DLC-2 (DATA LINK CONNECTOR-2) FOR SHORT TO GROUND
• Is there continuity between SST connector terminal T and ground?
Yes
Repair wiring harness between ABS/TCS HU/CM and DLC-2.
No
Replace ABS/TCS HU/CM (communication circuit malfunction in ABS/TCS HU/CM).