B1277

Control System DTCs

DTC Troubleshooting: B1275, B1276, B1277, B1278

DTC B1275 : Headlight Switch OFF Position Circuit Malfunction
DTC B1276 : Headlight Switch PARKING Position Circuit Malfunction
DTC B1277 : Headlight Switch AUTO Position Circuit Malfunction
DTC B1278 : Headlight Switch ON Position Circuit Malfunction

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

1. Problem verification:

-1. Check the parameter(s) below with the HDS.


















Do the current condition(s) match the threshold?
-YES- Intermittent failure, the system is OK at this time. Check for loose or poor connections.
-NO- Go to step 2.

2. Exterior lights system check:

-1. Check the parameter(s) below with the HDS.





Is data list value OFF, not ON?
-YES- Go to step 5.
-NO- Go to step 3.

3. Determine possible failure area (combination light switch, others):

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

-2. Disconnect the following connector.





-3. Check the parameter(s) below with the HDS.





Has the data list value changed from ON to OFF?
-YES- Replace the combination light switch.
-NO- Go to step 4.

4. Shorted wire check (H/L OFF SW, H/L ON SW, SMALL LT SW lines):

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

-2. Disconnect the following connector.





-3. Check for continuity between test points 1 and 2 individually.


















Is there continuity?
-YES- Repair a short to ground in the wire.
-NO- The H/L OFF SW, H/L ON SW, and SMALL LT SW wires are OK. Faulty MICU; replace the under-dash fuse/relay box Under-Dash Fuse/Relay Box Removal and Installation.

5. Determine possible failure area (combination light switch, others):

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

-2. Disconnect the following connector.





-3. Connect terminals A and B with a jumper wire.


















-4. Check the parameter(s) below with the HDS.





Has the data list value changed from OFF to ON?
-YES- Replace the combination light switch Service and Repair.
-NO- Go to step 6.

6. Open wire check (H/L OFF SW, H/L ON SW, SMALL LT SW, COMBI SW GND (LT) lines):

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

-2. Disconnect the following connector.





-3. Check for continuity test points 1 and 2.






















Is there continuity?
-YES- The H/L OFF SW, H/L ON SW, SMALL LT SW, and COMBI SW GND (LT) wires are 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 wire.