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/Installation

NO - Go to step 7.


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

8. Disconnect the combination light switch 12P connector.

9. Turn the ignition switch to ON (II).

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

11. 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 both values now showing OFF?
YES - Go to step 15.

NO - Go to step 12.


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

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

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

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

NO - Faulty MICU; replace the under-dash fuse/relay box.






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

16. Do the combination light switch test. Service and Repair

Is the combination light switch OK?
YES - Go to step 17.

NO - Replace the combination light switch.


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

18. Check for continuity between under-dash fuse/relay box connector S (20P) terminals and combination light switch 12P connector terminals as shown:





Is there continuity?
YES - Go to step 19.

NO - Repair an open in the wire.






19. Check for continuity between under-dash fuse/relay box connector S (20P) terminals No. 5 and No. 18, and between connector S (20P) terminals No. 5 and No. 19 respectively.

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

NO - Faulty MICU; replace the under-dash fuse/relay box.