Code No. C1291:
Reverse Signal (Seizure)
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.
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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).
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STEP 1. M.U.T.-III CAN bus diagnosis.
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Use M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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Go to Step 3.
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Repair the CAN bus lines (Refer to GROUP 54C -
CAN Bus Diagnosis Table ).
On completion, go to Step 2.
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STEP 2. Diagnosis code recheck after resetting CAN bus lines
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(1)Turn the ignition switch to the "ON" position.
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(2)Erase the diagnosis code.
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(3)Turn the ignition switch to the "LOCK" (OFF) position.
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(4)Turn the ignition switch to the "ON" position.
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(5)Check if the diagnosis code is set.
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(6)Turn the ignition switch to the "LOCK" (OFF) position.
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Q.
Is diagnosis code No. C1291 set?
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Go to Step 3.
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Intermittent malfunction (Refer to GROUP 00 -
How to Cope with Intermittent
Malfunctions).
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STEP 3. Check the back-up lamp
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(1)Turn the ignition switch to the "ON" position.
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(2)Check how the back-up lamp operates correctly when you move the shift lever. OK:
When the shift lever is moved to reverse position: Illuminate When the shift lever is moved to any position other than reverse: OFF
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Q.
Is the check result normal?
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Go to Step 10.
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NO <comes on> : The back-up lamp 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.
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NO <goes out> : The back-up lamp 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.
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STEP 4. Check the back-up lamp switch
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- Refer to GROUP 22B -
Transmission, Inspection. <4G64-2WD>
- Refer to GROUP 22C -
Transmission, Inspection. <4D56-2WD>
- Refer to GROUP 22E -
Transmission, Inspection. <4G64-4WD>
- Refer to GROUP 22F -
Transmission, Inspection. <4D56-4WD>
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Q.
Is the check result normal?
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Go to Step 5.
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NO <4G64-2WD> : Replace the back-up lamp switch (Refer to GROUP 22B -
Transmission).
Then go to Step 12.
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NO <4D56-2WD> : Replace the back-up lamp switch (Refer to GROUP 22C -
Transmission).
Then go to Step 12.
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NO <4G64-4WD> : Replace the back-up lamp switch switch (Refer to GROUP 22E -
Transmission).
Then go to Step 12.
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NO <4D56-4WD> : Replace the back-up lamp switch (Refer to GROUP 22F -
Transmission).
Then go to Step 12.
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STEP 5. Measure the resistance at the back-up lamp switch connector
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(1)Remove the back-up lamp switch connector, junction block connector and ETACS-ECU
connector.
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(2)Check the back-up lamp switch connector.
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(3)Disconnect the connector and measure at the wiring harness side.
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(4)Measure the resistance between the back-up lamp switch connector terminals and
body earth. OK: No continuity
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Q.
Is the check result normal?
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Go to Step 10.
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The back-up lamp 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.
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STEP 6. Check the fuse No.21
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Q.
Is the check result normal?
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Go to Step 7.
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Go to Step 9.
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STEP 7. Check the back-up lamp switch
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- Refer to GROUP 22B -
Transmission, Inspection. <4G64-2WD>
- Refer to GROUP 22C -
Transmission, Inspection. <4D56-2WD>
- Refer to GROUP 22E -
Transmission, Inspection. <4G64-4WD>
- Refer to GROUP 22F -
Transmission, Inspection. <4D56-4WD>
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Q.
Is the check result normal?
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Go to Step 8.
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NO <4G64-2WD> : Replace the back-up lamp switch (Refer to GROUP 22B -
Transmission).
Then go to Step 12.
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NO <4D56-2WD> : Replace the back-up lamp switch (Refer to GROUP 22C -
Transmission).
Then go to Step 12.
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NO <4G64-4WD> : Replace the back-up lamp switch (Refer to GROUP 22E -
Transmission).
Then go to Step 12.
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NO <4D56-4WD> : Replace the back-up lamp switch (Refer to GROUP 22F -
Transmission).
Then go to Step 12.
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STEP 8. Measure the resistance at the back-up lamp switch connector
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(1)Remove the back-up lamp switch connector, junction block connector and ETACS-ECU
connector.
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(2)Check the back-up lamp switch connector.
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(3)Disconnect the connector and measure at the wiring harness side.
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(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).
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Q.
Is the check result normal?
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Go to Step 10.
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The back-up lamp 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.
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STEP 9. Measure the resistance at the back-up lamp switch connector
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(1)Remove the back-up lamp switch connector, junction block connector and ETACS-ECU
connector.
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(2)Check the back-up lamp switch connector.
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(3)Disconnect the connector and measure at the wiring harness side.
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(4)Measure the resistance between the back-up lamp switch connector terminals and
body earth. OK: No continuity
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Q.
Is the check result normal?
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Replace the fuse No.21. Then go to Step 12.
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The back-up lamp 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.
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STEP 10. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Turn the ignition switch to the "ON" position.
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(2)Erase the diagnosis code.
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(3)Turn the ignition switch to the "LOCK" (OFF) position.
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(4)Turn the ignition switch to the "ON" position.
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(5)Move the shift lever to the reverse position, and hold it for at least one second.
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(6)Move the shift lever to the neutral position, and hold it for at least one second.
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(7)Check if the diagnosis code is set.
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(8)Turn the ignition switch to the "LOCK" (OFF) position.
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Q.
Is code No. C1291 set?
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Replace the ETACS-ECU (Refer to GROUP 54A -
ETACS-ECU). Then go to Step
11.
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Intermittent malfunction (Refer to GROUP 00 -
How to Cope with Intermittent
Malfunctions).
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STEP 11. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Turn the ignition switch to the "ON" position.
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(2)Erase the diagnosis code.
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(3)Turn the ignition switch to the "LOCK" (OFF) position.
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(4)Turn the ignition switch to the "ON" position.
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(5)Move the shift lever to the reverse position, and hold it for at least one second.
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(6)Move the shift lever to the neutral position, and hold it for at least one second.
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(7)Check if the diagnosis code is set.
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(8)Turn the ignition switch to the "LOCK" (OFF) position.
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Q.
Is code No. C1291 set?
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Replace the hydraulic unit assembly (integrated with ASTC-ECU). Then go to Step
12.
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The procedure is complete.
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STEP 12. Check whether the diagnosis code is set again.
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Check again if the diagnosis code is set.
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(1)Turn the ignition switch to the "ON" position.
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(2)Erase the diagnosis code.
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(3)Turn the ignition switch to the "LOCK" (OFF) position.
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(4)Turn the ignition switch to the "ON" position.
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(5)Move the shift lever to the reverse position, and hold it for at least one second.
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(6)Move the shift lever to the neutral position, and hold it for at least one second.
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(7)Check if the diagnosis code is set.
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(8)Turn the ignition switch to the "LOCK" (OFF) position.
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Q.
Is code No. C1291 set?
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Return to Step 1.
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The procedure is complete.
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