Code No. U0126: SAS CAN Timeout

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 ).
If diagnosis code No. U0126 is set in ACC/FCM-ECU, always diagnose the CAN bus line. If there is any fault in the CAN bus lines, an incorrect diagnosis code may be set. In this case, the set diagnosis code is not highly reliable.
Whenever the ECU is replaced, ensure that the CAN bus lines are normal.
When the column switch assembly (Integrated with steering wheel sensor) is replaced, calibrate the steering wheel sensor.
When the ACC/FCM-ECU is replaced, calibrate the radar (refer to ).

OPERATION

The ACC/FCM-ECU communicates with the steering wheel sensor via the CAN bus lines.

DIAGNOSIS CODE SET CONDITION

The ACC/FCM-ECU receives the steering wheel sensor signals from the steering wheel sensor via the CAN bus lines. When these signals cannot be received, the ECU sets this diagnosis code.

PROBABLE CAUSES

Malfunction of the CAN bus line
Malfunction of the column switch assembly (Integrated with steering wheel sensor)
Malfunction of the ACC/FCM-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.

Use M.U.T.-III to perform the CAN bus diagnosis.

Q. Is the check result normal?

	Go to Step 2.

	Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.

STEP 2. Use M.U.T.-III to confirm a diagnosis code of other systems.

Check if the diagnosis code is set in the steering wheel sensor.

Q. Is the diagnosis code set?

	Troubleshoot the steering wheel sensor diagnosis code.

	Go to Step 3.

STEP 3. Use M.U.T.-III to confirm a diagnosis code of other systems.

Check whether an steering wheel sensor "time-out" related diagnosis code is set in other ECUs.

Q. Is the diagnosis code set?

	Replace the column switch assembly (Integrated with steering wheel sensor) correctly (Refer to GROUP 54A - Column Switch).

	Go to Step 4.

STEP 4. Check whether the diagnosis code is set again.

Check again if the diagnosis code is set in the ACC/FCM-ECU.

(1)Erase the diagnosis code.

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

(3)Start the engine.

(4)Press the FCM and UMS ON/OFF switch to turn the FCM system to ON.

(5)On completion, check that the diagnosis code is set again.

Q. Is diagnosis code No. U0126 set?

	Replace the ACC/FCM-ECU (Refer to ).

	Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions).