Inspection Procedure 4: When the ignition switch is turned to the "ON" position (engine after start-up), Brake warning lamp remains illuminated.

caution

If the ABS-ECU has a malfunction, or the battery voltage increases abnormally, the ABS-ECU is deactivated, and then the brake warning lamp is illuminated, disabling the communication with M.U.T.-III. When the communication with M.U.T-III cannot be performed, carry out the troubleshooting according to the Inspection Procedure 1. (Refer to

note

The following inspection must be performed only when the communication with M.U.T.-III can be performed (ABS-ECU power supply is normal) with no diagnosis code being set.

OPERATION

When the power is supplied, the ABS-ECU illuminates the brake warning lamp for approximately 3 seconds by turning the warning lamp drive transistor inside the ABS-ECU (ON → OFF). Then, if the system has no abnormality, the ABS-ECU turns off the warning lamp by turning the warning lamp drive transistor (OFF → ON).

COMMENT ON TROUBLE SYMPTOM

For the cause that the lamp remains illuminated, the following malfunctions are suspected.

Malfunction of the inversion circuit in the combination meter
The lamp drive signal is not input to the inversion circuit in the combination meter.

PROBABLE CAUSES

The most likely causes for this case are:

Combination meter defect
Open circuit of the lamp drive signal line
Malfunction of the ABS-ECU

DIAGNOSIS

STEP 1. Inspect with the ABS-ECU connector D-250.

(1)Disconnect ABS-ECU connector D-250, and check at the harness side.

(2)Turn the ignition switch to the "ON" position.

(3)Connect the ABS-ECU connector D-250 (harness side) terminal No. 45 to the body earth, and check the brake warning lamp status.
OK: Illuminates

Q. Is the check result normal?

	Replace the ABS-ECU. Then go to Step 3.

	Go to Step 2.

STEP 2. Check the harness wire between the combination meter connector D-02 terminal 45 and ABS-ECU connector D-250 terminal 39.

note

Prior to the wiring harness inspection, check intermediate connector D-230, and repair if necessary.

Q. Is the check result normal?

	Replace the combination meter.

	Go to Step 3.

STEP 3. Retest the system.

Q. Does the ABS warning lamp extinguish?

	The procedure is complete.

	Start over at Step 1.