B1079

Control System DTCs

DTC Troubleshooting: B1079

DTC B1079 : Daytime Running Light Malfunction

NOTE: Refer to the Electrical Wiring Diagrams for the location of the under-dash fuse/relay box connectors.

1. Problem verification:

-1. Turn the headlights switch OFF, and apply the parking brake.

-2. Clear the DTCs with the HDS.

-3. Release the parking brake.

-4. Turn the ignition switch to LOCK (0) and then back to ON (II).

-5. Check for DTCs with the HDS.





Is DTC B1079 indicated?
-YES- Go to step 2.
-NO- Intermittent failure, the system is OK at this time. Check for loose or poor connections.

2. Fuse check:

-1. Turn the ignition switch to LOCK (0).

-2. Check the following fuses.





Is each fuse OK?
-YES- Go to step 3.
-NO- Replace the fuse. If the fuse blows again, repair a short to ground in the No. B38 (10 A) and/or No. B39 (10 A) fuse circuit(s).

3. MICU check:

-1. Turn the headlight (high beam) ON.

Do both headlights (high beam) come on?
-YES- Faulty MICU; replace the under-dash fuse/relay box Under-Dash Fuse/Relay Box Removal and Installation.
-NO- Go to step 4.

4. Headlight bulb visual check:

-1. Check the headlight (high beam) bulbs.

Are the headlight (high beam) bulbs OK?
-YES- Go to step 5.
-NO- Replace the faulty bulb.

5. Open wire check (L H/L HI line):

-1. Disconnect the following connectors.





-2. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- The L H/L HI wire is OK. Go to step 6.
-NO- Repair an open or high resistance in the wire.

6. Open wire check (R H/L HI line):

-1. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- The R H/L HI wire is OK. Go to step 7.
-NO- Repair an open or high resistance in the wire.

7. Open wire check (GND line):

-1. Check for continuity between test points 1 and 2 individually.









Is there continuity?
-YES- The GND wire is OK. Faulty MICU; replace the under-dash fuse/relay box Under-Dash Fuse/Relay Box Removal and Installation.
-NO- Repair an open or high resistance in the ground wire or poor ground (G301).