Inspection Procedure 6: ABS warning lamp stays ON after the engine is started.

caution

If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - Troubleshooting ).
Whenever ECU is replaced, ensure that the CAN bus lines are normal.
When the hydraulic unit assembly (integrated with ASTC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G sensor (Refer to ).

ASTC-ECU sends the illumination request signal of the ABS warning lamp to the combination meter via CAN communication.
ASTC-ECU illuminates the ABS warning lamp for approximately 3 seconds for bulb check with the ignition switch turned to the ON position.

This may be caused by faults in the CAN bus line, combination meter or ASTC-ECU.

Damaged wiring harness and connectors
Malfunction of the combination meter
ASTC-ECU malfunction
Control stop due to the low voltage

note Due to the abnormality in the supply voltage, the diagnosis code may not be set even when the ABS warning lamp is illuminated.

DIAGNOSIS PROCEDURE

Use M.U.T.-III to diagnose the CAN bus lines.

Go to Step 2.

Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting

). Then go to Step 6.

Use M.U.T.-III to check the diagnosis code for the ASTC system.

Carry out the diagnosis for the diagnosis code (Refer to

Go to Step 3.

Refer to

Go to Step 4.

Diagnose the power supply circuit of the ASTC-ECU (Refer to

Using M.U.T.-III, check that diagnosis code is not set by the combination meter system.

Diagnose the combination meter (Refer to GROUP 54A - Combination Meter/Diagnosis Code

). Then go to Step 6.

Go to Step 5.

Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions

Replace the hydraulic unit assembly (integrated with ASTC-ECU) (Refer to

This diagnosis is complete.

Replace the hydraulic unit assembly (integrated with ASTC-ECU) (Refer to