DTC B3138: All Door Lock Circuit High: Testing

WARNING: This page is about a different car, the 1999 Pontiac Grand Am and 1999 Oldsmobile Alero. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If circuit is shorted to ground, fuse will blow. Check fuse before performing diagnostics.

Perform BCM DIAGNOSTIC SYSTEM CHECK under SYSTEM TESTS. Go to next step.
Check operation of power door locks. Repair as necessary. See appropriate wiring diagram in POWER DOOR LOCKS & REMOTE KEYLESS ENTRY SYSTEMS article. Go to next step.
If all door locks operate properly, go to step 11 . If all door locks do not operate properly, go to next step.
Replace door unlock relay with known-good relay. Door unlock relay is located on in the LH instrument panel junction block. If door locks now operates properly, go to next step. If door locks do not operate properly, go to step 6 .
Replace door unlock relay. After repairs, go to step 11 .
Disconnect LH instrument panel junction block connector C1. Using DVOM, measure voltage between LH instrument panel junction block connector C1 terminal F10 (Light Blue wire) and ground. See WIRING DIAGRAMS . If zero volts is indicated, go to next step. If any voltage is indicated, go to step 8 .
Replace LH instrument panel junction block. After repairs, go to step 11 .
Disconnect BCM connector C3. Using DVOM, measure voltage of Light Blue wire between BCM connector C3 terminal A8 and LH instrument panel junction block connector C1 terminal F10. See Figure . If zero volts is indicated, go to step 10 . If any voltage is indicated, go to next step.
Repair short to battery voltage in Light Blue wire between BCM and door unlock relay. After repairs, go to step 11 .
Replace BCM. See BODY CONTROL MODULE under REMOVAL & INSTALLATION. After repairs, go to BCM DIAGNOSTIC SYSTEM CHECK under SYSTEM TESTS.
Using scan tool, clear DTCs. Go to BCM DIAGNOSTIC SYSTEM CHECK under SYSTEM TESTS.