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DTC 12: Diagnostic System Check: Testing

WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
  1. 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.
  2. Attempt to enter Body Control Module (BCM) diagnostic mode. See BODY CONTROL MODULE SYSTEM DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. If SECURITY indicator does not flash DTCs, go to next step. If SECURITY indicator flashes DTCs, system is operating properly. Perform appropriate test in accordance with DTC displayed. See DIAGNOSTIC TROUBLE CODE DEFINITIONS e under SELF-DIAGNOSTIC SYSTEM.
  3. Turn ignition switch to RUN position. Operate power windows, if equipped. If not equipped with power windows or power windows do not operate, go to next step. If power windows operate, go to step  7.
  4. Turn ignition switch to OFF position. Disconnect BCM 6-pin harness connector C2. BCM is located behind right side of instrument panel, near blower motor. See Figure. Connect test light between ground and BCM connector C2 terminal "C" (Dark Blue wire). See Figure. If test light illuminates, go to next step. If test light does not illuminate, go to step  6.
  5. 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 does not flash DTCs, go to next step. If SECURITY indicator flashes DTCs, system is operating properly. Perform appropriate test in accordance with DTC displayed. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  under SELF-DIAGNOSTIC SYSTEM.
  6. Replace BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. Program BCM. See BODY CONTROL MODULE  under PROGRAMMING.
  7. Turn ignition switch to OFF position. Disconnect BCM 16-pin harness connector C3. BCM is located behind right side of instrument panel, near blower motor. See Figure. Connect a fused jumper wire between ground and BCM harness connector C3 terminal C12 (Gray wire). See Figure. If SECURITY indicator illuminates, go to next step. If SECURITY indicator does not illuminate, go to step  9.
  8. 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  under REMOVAL & INSTALLATION. Program BCM. See BODY CONTROL MODULE  under PROGRAMMING.
  9. Remove instrument cluster. See ANALOG INSTRUMENT PANELS - CAMARO & FIREBIRD article. Disconnect Instrument Panel Cluster (IPC) 34-pin harness connector. Connect a test light between ground and IPC harness connector terminal A10 (Orange wire). See Fig 1. If test light illuminates, go to next step. If test light does not illuminate, go to step  11.
  10. Check for an open circuit or faulty connection in Gray wire between IPC and BCM. Repair circuit or connection as necessary. If circuit and connection are okay, replace IPC. See ANALOG INSTRUMENT PANELS - CAMARO & FIREBIRD article.
  11. Repair open in Orange wire between instrument cluster and instrument panel fuse block.
Fig 1: Identifying Instrument Panel Cluster Harness Connector Terminals
G93C41402Courtesy of GENERAL MOTORS CORP.
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