DTC Troubleshooting: B1275, B1276, 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
  1. Clear the DTCs with the HDS.
  1. Turn the ignition switch to LOCK (0) and then back to ON (II).
  1. Turn the combination light switch POSITION (SMALL) and ON (low beam) position, and then OFF position.
  1. Clear the DTCs with the HDS.
Is DTC B1275, B1276, or B1278 indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure, the system is OK at this time. Check for loose or poor connections.■
  1. Select LIGHTING from the BODY ELECTRICAL system select menu, and enter the DATA LIST.
  1. Check each combination light switch position value with the DATA LIST menu.

    When the combination light switch is turned OFF

    Data List
    Value
    Headlight Switch (OFF)
    ON
    Headlight Switch (SMALL)
    OFF
    Headlight Switch (HEADLIGHT)
    OFF


    When the combination light switch is turned to POSITION (SMALL)

    Data List
    Value
    Headlight Switch (OFF)
    OFF
    Headlight Switch (SMALL)
    ON
    Headlight Switch (HEADLIGHT)
    OFF


    When the combination light switch is turned ON (HEADLIGHT)

    Data List
    Value
    Headlight Switch (OFF)
    OFF
    Headlight Switch (SMALL)
    ON
    Headlight Switch (HEADLIGHT)
    ON

Are all data list values correct?
YES -
Faulty driver's MICU; replace the driver's under-dash fuse/relay box. ■
NO -
Go to Step 7 .
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect the combination light switch 12P connector.
  1. Turn the ignition switch to ON (II).
  1. Select LIGHTING from the BODY ELECTRICAL system select menu, and enter the DATA LIST.
  1. Check each combination light switch position value with the DATA LIST menu.

    When the combination light switch is turned OFF

    Data List
    Value
    Headlight Switch (OFF)
    OFF
    Headlight Switch (SMALL)
    OFF
    Headlight Switch (HEADLIGHT)
    OFF

Are all data list values indicated OFF?
YES -
Go to Step 15 .
NO -
Go to Step 12 .
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect driver's under-dash fuse/relay box connector R (24P).
  1. Check for continuity between body ground and 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. ■
  1. Turn the ignition switch to LOCK (0).
  1. Do the combination light switch test.
Is the combination light switch OK?
YES -
Go to Step 17 .
NO -
Replace the combination light switch.■
  1. Disconnect driver's under-dash fuse/relay box connectors R (24P).