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Home >> Chevrolet >> 2001 >> Camaro Base, 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 33 (Charging System) >> Diagnostic Tests >> DTC P0620: Fault Detection Circuit Malfunction >> Diagnostic Procedure

Diagnostic Procedure

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. If diagnostic system check was not performed, perform ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK  under ON-VEHICLE TESTING. If diagnostic system check was performed, go to next step.
  2. Turn ignition switch to OFF position. Disconnect generator. Measure voltage between generator turn-on signal circuit and ground. Start engine. Using scan tool, command generator ON and OFF. If voltage change is 0.0-5.0 volt, problem is intermittent. Check wiring and connections. If voltage change is not 0.0-5.0 volt, go to next step.
  3. Test generator turn-on signal circuit for a high resistance or and open. If problem exists, repair circuit as necessary. After repair, go to step  6 . If problem does not exist, go to next step.
  4. Inspect PCM harness connector for poor connections. If problem exists, repair as necessary. After repair, go to step  6 . If problem does not exist, go to next step.
  5. Replace PCM. See REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. Program PCM. After repair, go to next step.
  6. Review and record scan tool Fail Records data. Using scan tool, clear DTCs. Operate vehicle within Fail Records conditions as noted. Using scan tool, observe Specific DTC Information for DTC P0620. If scan tool indicates DTC P0620 failed this ignition, go to step  2 . If scan tool indicates DTC P0620 passed this ignition, system is okay.