Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2000 Pontiac Firebird Formula, AutomaticFACTORY OEM SERVICE PROCEDURE
DTC 12: Diagnostic System Check: Testing
- Turn ignition switch to RUN position. If SECURITY indicator comes on, go to next step. If SECURITY indicator does not come on, go to step 3 .
- Attempt to enter Body Control Module (BCM) diagnostic mode. See BODY CONTROL SYSTEM DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. If SECURITY indicator flashes DTCs, system is operating properly. Go to appropriate diagnostic procedure. See BCM DTC DEFINITIONS table under SELF-DIAGNOSTIC SYSTEM. If SECURITY indicator does not flash DTCs, go to next step.
- Turn ignition switch to RUN position. Operate power windows. If power windows operate, go to step 7 . If power windows do not operate, go to next step.
- Turn ignition switch to OFF position. Disconnect BCM connector C2. Connect test light between BCM connector C2 terminal "C" (Dark Blue wire) and ground. See Figure . If test light comes on, go to next step. If test light does not come on, go to step 6 .
- Repair short to ground in Dark Blue wire between BCM and instrument panel fuse block. After repairs, attempt to enter BCM diagnostic mode. If SECURITY indicator flashes DTCs, system is operating properly. Go to appropriate diagnostic procedure. See BCM DTC DEFINITIONS table under SELF-DIAGNOSTIC SYSTEM. If SECURITY indicator does not flash DTCs, go to next step.
- Replace BCM. See BODY CONTROL MODULE (BCM) under REMOVAL & INSTALLATION.
- Turn ignition switch to OFF position. Disconnect BCM connector C3. Connect a fused jumper wire between BCM connector C3 terminal C12 (Gray wire) and ground. If SECURITY indicator comes on, go to next step. If SECURITY indicator does not come on, go to step 9 .
- Check for a faulty connection at BCM connector C3 terminal C12 (Gray wire). Repair connection as necessary. If connection is okay, replace BCM. See BODY CONTROL MODULE (BCM) under REMOVAL & INSTALLATION.
- Remove instrument cluster. See appropriate ANALOG INSTRUMENT PANELS article. Disconnect instrument cluster connector. Connect a test light between instrument cluster connector terminal A10 (Orange wire) and ground. See Fig 1 . If test light comes on, go to next step. If test light does not come on, go to step 11 .
- Check for an open circuit or faulty connection in Gray wire between instrument cluster and BCM. Repair circuit or connection as necessary. If circuit and connection are okay, replace instrument cluster IPC. See appropriate ANALOG INSTRUMENT PANELS article.
- Repair open in Orange wire between instrument cluster and instrument panel fuse block.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.