B1078

DTC Troubleshooting: B1078

DTC B1078:

Daytime Running Lights Malfunction (Canada)

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. Press the parking brake pedal.

4. Check for DTCs with the HDS.

Is DTC B1078 indicated?

YES -

Go to step 5.

NO -

Intermittent failure, the system is OK at this time. Check for loose or poor connections.�

5. Turn the headlight high beam ON.

Do both headlights come on?

YES -

Go to step 6.

NO -

Go to step 9.

6. Turn the headlight switch OFF.

7. Select LIGHTING SYSTEM from the BODY ELECTRICAL SYSTEM SELECT menu, and enter the DATA LIST.

8. Check the ON/OFF information of the DRL Command in the DATA LIST.

Is the information indicator ON?

YES -

Check the PUR wire between under-hood fuse/relay box connector H (14P) terminal No. 3 and the daytime running lights relay for an open/short. If OK, replace the daytime running lights relay.�

NO -

Go to relay control module input test Relay Control Module Input Test.�

9. Check the No. 3 (10 A) and No. 5 (10 A) fuses in the under-hood fuse/relay box.

Are both fuses OK?

YES -

Go to step 10.

NO -

Replace the blown fuse and recheck the system.�

10. Check the headlight bulbs.

Are both bulbs OK?

YES -

Go to step 11.

NO -

Replace the blown bulb and recheck the system. If the fuse is blown again, repair a short in the wire.�

11. Disconnect the 2P connector from each headlight high beam.

12. Disconnect under-hood fuse/relay box connector H (14P).

13. Check for continuity between left headlight high beam 2P connector terminal No. 2 and under-hood fuse/relay box connector H (14P) terminal No. 8, and between right headlight high beam 2P connector terminal No. 2 and under-hood fuse/relay box connector H (14P) terminal No. 10.





Is there continuity?

YES -

Go to step 14.

NO -

Repair an open or high resistance in the wire.�

14. Check for continuity between each headlight high beam 2P connector terminal No. 1 and body ground.





Is there continuity?

YES -

Faulty relay control module; replace the under-hood fuse/relay box Under-Hood Fuse/Relay Box Removal and Installation.�

NO -

Check the daytime running lights relay (left headlight only) Power Relay Test. If the relay is OK, repair an open or high resistance in the wire or poor ground (G201, G301).�