If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Diagnose the CAN bus lines before the diagnosis codes (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
OPERATION
ASTC-ECU monitors if the lever is shifted to the reverse position.
DIAGNOSIS CODE SET CONDITIONS
This code is set 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
The most likely causes for this diagnosis code to set is:
Damaged wiring harness or connector
Malfunction of the back-up lamp switch <M/T>
Malfunction of the inhibitor switch <A/T>
Malfunction of the hydraulic unit assembly (integrated with ASTC-ECU)
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. Check whether the diagnosis code is reset.
(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 code No.C1291 set?
Go to Step 3.
The procedure is complete.
STEP 3. Check ASTC-ECU connector A-48 and back-lamp switch connector B-02 <M/T> or inhibitor switch connector B-14 <A/T> for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q.
Is the check result normal?
Go to Step 4.
NO <M/T> : Check the back-lamp switch. (Refer to GROUP 22C, Transmission inspection .) Then go to Step 5.
NO <A/T> : Check if the automatic transmission outputs a diagnosis code. (Refer to GROUP 23A, Troubleshooting .) Then go to Step 5.
STEP 4. Check the harness wires between ASTC-ECU connector A-48 terminal 39 and back-lamp switch connector B-02 terminal 1 <M/T> or inhibitor switch connector B-14 terminal 8 <A/T>.
Check the short to power supply between each harness connector.
Q.
Is the check result normal?
Go to Step 5.
Repair the wiring harness. Then go to Step 6.
STEP 5. Check whether the diagnosis code is reset.
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)Check if the diagnosis code is set.
(6)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 6.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
STEP 6. Check whether the diagnosis code is reset.
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)Check if the diagnosis code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.
)
Go to Step 3.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnosis table 
). On completion, go to Step 2.)
)
)
: Check the back-lamp switch. (Refer to GROUP 22C, Transmission inspection