Code No. C1294: Abnormal rear differential lock detection circuit

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 ).

The rear differential lock detection switch output signal is sent to ASTC-ECU via the CAN bus lines from transfer-ECU.

This diagnosis code will be set when the transfer-ECU detects a fault in the rear differential lock system.

Current trouble

Past trouble

Carry out diagnosis with particular emphasis on wiring harness and connector failures between ASTC-ECU and the transfer-ECU. For diagnosis procedures, refer to How to treat past trouble (GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).

DIAGNOSIS PROCEDURE

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

	Go to Step 3.

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

	Go to Step 3.

	This diagnosis is complete.

Check whether a diagnosis code is set in the transfer-ECU (Refer to GROUP 23A - Troubleshooting <SS4II>

	Troubleshoot the transfer-ECU diagnosis code. Then go to Step 5.

	Go to Step 4.

Check whether an transfer-ECU "time-out" related diagnosis code is set in other ECUs.

	Replace the transfer-ECU. (Refer to GROUP 23A - Transfer-ECU .) Then go to Step 5.

	Go to Step 5.

Check again if the diagnosis code is set.

(1)Erase the set diagnosis code.

(2)Ignition switch: "LOCK" (OFF)

(3)Ignition switch: "ON"

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

	The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).