Inspection Procedure 5: The brake warning lamp remains illuminated after the engine is started.




caution If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Diagnose the CAN bus lines before the diagnosis codes (Refer to GROUP 54C, CAN bus-line diagnostic flow ).

OPERATION


By the input from the brake warning lamp circuit, ASTC-ECU controls ON/OFF of the brake warning lamp.

COMMENT


Carry out troubleshooting with particular emphasis on the possibility of short to earth between ASTC-ECU and the brake warning lamp.

PROBABLE CAUSES



DIAGNOSIS

STEP 1. Check the ASTC-ECU connector A-48, intermediate connector C-13, and combination meter connector C-113 for loose, corroded or damaged terminals, or terminals pushed back in the connector.




Q. Is the check result normal?

Go to Step 2.

Repair or replace the damaged component(s). Then go to Step 6.

STEP 2. Check the harness wires between ASTC-ECU connector A-48 (terminal 35) and intermediate connector C-13 (terminal 15).



Q. Is the check result normal?

Go to Step 3.

Repair the wiring harness. Then go to Step 6.

STEP 3. Check the harness wires between intermediate connector C-13 (terminal 15) and combination meter connector C-113 (terminal 17).



Q. Is the check result normal?

Go to Step 4.

Repair the wiring harness. Then go to Step 6.

STEP 4. Retest the system

Q. Turn the ignition switch to the "ON" position. Do the brake warning lamp illuminate for three seconds, and then go out after the engine starts?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .
Replace the combination meter.Then go to Step 5.

STEP 5. Retest the system

Q. Turn the ignition switch to the "ON" position. Do the brake warning lamp illuminate for three seconds, and then go out after the engine starts?
The procedure is complete.
Replace the hydraulic unit (integrated with ASTC-ECU).Then go to Step 6.

STEP 6. Retest the system

Q. Turn the ignition switch to the "ON" position. Do the brake warning lamp illuminate for three seconds, and then go out after the engine starts?
The procedure is complete.
Return to Step 1.