Code No. C1291: Reverse signal (seizure) <M/T>

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 - CAN Bus Diagnostics Table ).
Whenever ECU is replaced, ensure that the CAN bus lines are normal.
When the hydraulic unit (integrated with ASTC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G and yaw rate sensor (Refer to ).

OPERATION

The back-up lamp switch output signal is sent to ASTC-ECU via the CAN bus lines.

DIAGNOSIS CODE SET CONDITION

When the power supply and wheel speed sensor are normal and ASTC-ECU receives the signal that the shift lever is at the reverse position while the vehicle drives at 50 km/h or more.

PROBABLE CAUSES

Current trouble

Blown fuse
Damaged wiring harness or connector
Malfunction of the back-up lamp switch
Malfunction of the ETACS-ECU
Malfunction of the hydraulic unit assembly (integrated with ASTC-ECU)

Past trouble

Carry out diagnosis with particular emphasis on the back-up lamp switch, connector(s) or wiring harness between the back-up lamp switch to the junction block or ETACS-ECU. For diagnosis procedures, refer to How to treat past trouble (GROUP 00 - How to Use Troubleshooting/Inspection Service Points ).

DIAGNOSIS PROCEDURE

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

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

Q. Is the check result normal?

	Go to Step 3.

	Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis Table ). On completion, go to Step 2.

STEP 2. Diagnosis code recheck after resetting CAN bus lines

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

(2)Erase the diagnosis code.

(3)Turn the ignition switch to the "LOCK" (OFF) position.

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

(5)Check if the diagnosis code is set.

(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is diagnosis code No. C1291 set?

	Go to Step 3.

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

STEP 3. Check the back-up lamp

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

(2)Check how the back-up lamp operates correctly when you move the shift lever.
OK:

When the shift lever is moved to R position: Illuminate
When the shift lever is moved to any position other than R: OFF

Q. Is the check result normal?

	Go to Step 10.

	NO <comes on> : The back-lamp switch circuit may be short. Repair the wiring harness wires or connectors between the back-up lamp switch and the ETACS-ECU connector back terminal or the junction block. Then go to Step 4.

	NO <goes out> : The back-lamp switch circuit may be open. Repair the wiring harness wires or connectors between the back-up lamp switch and the ETACS-ECU connector back terminal or the junction block. Then go to Step 6.

STEP 4. Check the back-up lamp switch

Refer to GROUP 22D - Transmission, Inspection . <2WD>
Refer to GROUP 22G - Transmission, Inspection . <4WD>

Q. Is the check result normal?

	Go to Step 5.

	NO <2WD> : Replace the back-lamp switch (Refer to GROUP 22D - Transmission ). Then go to Step 12.

	NO <4WD> : Replace the back-lamp switch (Refer to GROUP 22G - Transmission ). Then go to Step 12.

STEP 5. Measure the resistance at the back-up switch connector

(1)Remove the back-up lamp switch connector, junction block connector and ETACS-ECU connector.

(2)Check the back-up lamp switch connector.

(3)Disconnect the connector and measure at the wiring harness side.

(4)Measure the resistance between the back-up lamp switch connector terminals and body earth.
OK: No continuity

Q. Is the check result normal?

	Go to Step 10.

	The back-up lamp switch circuit may be short. Repair the wiring harness wires or connectors between the back-up lamp switch connector terminals and the junction block or ETACS-ECU connector. Then go to Step 12.

STEP 6. Check the fuse No.21

Q. Is the check result normal?

	Go to Step 7.

	Go to Step 9.

STEP 7. Check the back-up lamp switch

Refer to GROUP 22D - Transmission, Inspection . <2WD>
Refer to GROUP 22G - Transmission, Inspection . <4WD>

Q. Is the check result normal?

	Go to Step 8.

	NO <2WD> : Replace the back-lamp switch (Refer to GROUP 22D - Transmission ). Then go to Step 12.

	NO <4WD> : Replace the back-lamp switch (Refer to GROUP 22G - Transmission ). Then go to Step 12.

STEP 8. Measure the resistance at the back-up switch connector

(1)Remove the back-up lamp switch connector, junction block connector and ETACS-ECU connector.

(2)Check the back-up lamp switch connector.

(3)Disconnect the connector and measure at the wiring harness side.

(4)Measure the resistance between the back-up lamp switch connector terminals and junction block connector or ETACS-ECU connector.
OK: Continuity exists (2 Ω or less).

Q. Is the check result normal?

	Go to Step 10.

	The back-up lamp switch circuit may be open. Repair the wiring harness wires or connectors between the back-up lamp switch connector terminals and the junction block or ETACS-ECU connector. Then go to Step 12.

STEP 9. Measure the resistance at the back-up switch connector

(1)Remove the back-up lamp switch connector, junction block connector and ETACS-ECU connector.

(2)Check the back-up lamp switch connector.

(3)Disconnect the connector and measure at the wiring harness side.

(4)Measure the resistance between the back-up lamp switch connector terminals and body earth.
OK: No continuity

Q. Is the check result normal?

	Replace the fuse No.21. Then go to Step 12.

	The back-up lamp switch circuit may be short. Repair the wiring harness wires or connectors between the back-up lamp switch connector terminals and the junction block or ETACS-ECU connector, or replace the fuse No.21. Then go to Step 12.

STEP 10. Check whether the diagnosis code is set again.

Check again if the diagnosis code is set.

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

(2)Erase the diagnosis code.

(3)Turn the ignition switch to the "LOCK" (OFF) position.

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

(5)Move the shift lever to the R position, and hold it for at least one second.

(6)Move the shift lever to the neutral position, and hold it for at least one second.

(7)Check if the diagnosis code is set.

(8)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1291 set?

	Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ). Then go to Step 11.

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

STEP 11. Check whether the diagnosis code is set again.

Check again if the diagnosis code is set.

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

(2)Erase the diagnosis code.

(3)Turn the ignition switch to the "LOCK" (OFF) position.

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

(5)Move the shift lever to the R position, and hold it for at least one second.

(6)Move the shift lever to the neutral position, and hold it for at least one second.

(7)Check if the diagnosis code is set.

(8)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1291 set?

	Replace the hydraulic unit assembly (integrated with ASTC-ECU) (Refer to ). Then go to Step 12.

	The procedure is complete.

STEP 12. Check whether the diagnosis code is set again.

Check again if the diagnosis code is set.

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

(2)Erase the diagnosis code.

(3)Turn the ignition switch to the "LOCK" (OFF) position.

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

(5)Move the shift lever to the R position, and hold it for at least one second.

(6)Move the shift lever to the neutral position, and hold it for at least one second.

(7)Check if the diagnosis code is set.

(8)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is code No.C1291 set?

	Return to Step 1.

	The procedure is complete.