B1280

DTC Troubleshooting: B1280

DTC B1280: Turn Signal Switch Circuit Malfunction

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A. Troubleshooting - B-CAN System Diagnosis Test Mode A

1. Clear the DTCs with the HDS.

2. Turn the ignition switch to LOCK (0) and then back to ON (II).

3. Operate the turn signal switch in left and right positions, and wait for 6 seconds or more.

4. Check for DTCs with the HDS.

Is DTC B1280 indicated?
YES - Go to step 5.

NO - Intermittent failure, the system is OK at this time. Check for loose or poor connections.


5. Select LIGHTING from the BODY ELECTRICAL system select menu, then enter DATA LIST.

6. Check each turn signal switch position value with the DATA LIST menu.

When the turn signal switch is in left position





When the turn signal switch is in right position





Are all data list values correct?
YES - Faulty MICU; replace the under-dash fuse/relay box. Under-Dash Fuse/Relay Box Removal and Installation

NO - Go to step 7.


7. Disconnect the combination light switch 12P connector.

8. Check each turn signal switch position value with the DATA LIST menu.

When the turn signal switch is in left position





When the turn signal switch is in right position





Do both values now showing OFF?
YES - Replace the combination light switch. Combination Light Switch Test/Replacement

NO - Go to step 9.


9. Turn the ignition switch to LOCK (0).

10. Disconnect under-dash fuse/relay box connector S (20P).

11. Check for continuity between body ground and under-dash fuse/relay box connector S (20P) terminals No. 18 and No. 19.

Is there continuity?
YES - Repair a short to ground in the wire.

NO - Go to step 12.






12. Check for continuity between under-dash fuse/relay box connector S (20P) terminals No. 18 and No. 19.

Is there continuity?
YES - Repair a short between the wires.

NO - Replace the combination light switch.