B1278

DTC B1275: Combination Light Switch OFF Position Circuit Malfunction

DTC B1276: Combination Light Switch Parking (SMALL) Position Circuit Malfunction

DTC B1278: Combination Light Switch ON Position Circuit Malfunction

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in 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. Turn the combination light switch to the PARKING (SMALL) and the ON (low beam) positions, and then OFF position.
4. Wait for 6 seconds or more.
5. Check for DTCs with the HDS.

Is DTC B1275, B1276, or B1278 indicated?

YES - Go to step 6.

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

6. Select LIGHTING from the BODY ELECTRICAL system select menu, and enter the DATA LIST.
7. Check each combination light switch position value with the DATA LIST menu.






Are all data list values correct?

YES - Faulty driver's MICU; replace the driver's under-dash fuse/relay box.

NO - Go to step 8.

8. Turn the ignition switch to LOCK (0).
9. Disconnect the combination light switch 12P connector.
10. Turn the ignition switch to ON (II).
11. Select LIGHTING from the BODY ELECTRICAL system select menu, and enter the DATA LIST.
12. Check each combination light switch position value with the DATA LIST menu.






Are all data list values indicated OFF?

YES - Go to step 16.

NO - Go to step 13.

13. Turn the ignition switch to LOCK (0).
14. Disconnect driver's under-dash fuse/relay box connector R (24P).
15. Check for continuity between body ground and the driver's under-dash fuse/relay box connector R (24P) No. 6, No. 7, and No. 8 terminals individually.






Is there continuity?

YES - Repair a short to ground in the wire.

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

16. Turn the ignition switch to LOCK (0).
17. Do the combination light switch test.

Is the combination light switch OK?

YES - Go to step 18.

NO - Replace the combination light switch.

18. Disconnect driver's under-dash fuse/relay box connector R (24P).
19. Check for continuity between the driver's under-dash fuse/relay box connector R (24P) terminals and the combination light switch 12P connector terminals as shown:






Is there continuity?

YES - Go to step 20.

NO - Repair an open in the wire.

20. Check for continuity between the driver's under-dash fuse/relay box connector R (24P) terminals as shown:







Is there continuity?

YES - Repair a short between the wires.

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