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.
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HOMESERVICE MANUALSCHEVROLET1999CAVALIER Z24, 2D CONVERTIBLE, AUTOMATICREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROL SYSTEM - TESTS W/CODES - DTC P0453-P0656DTC P0620DTC P0620: GENERATOR PERFORMANCEDIAGNOSTIC PROCEDURES
1999 Chevrolet Cavalier Z24, 2D Convertible, Automatic
Diagnostic Procedures
1999 Chevrolet Cavalier Z24, 2D Convertible, AutomaticSECTION Diagnostic Procedures
- Perform On-Board Diagnostic (OBD) System Check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . After performing OBD system check, go to next step.
- Start and operate engine at idle. Using scan tool, monitor generator. If scan tool indicates that generator is on, go to step Β 4. If scan tool does not indicate that generator is on, go to next step.
- Turn ignition off. Disconnect generator harness connector. Connect a DVOM between generator "L" terminal and a known-good ground. Start engine. Using scan tool, command generator on. Monitor voltage reading on DVOM. If voltage reading changes from zero to 5 volts, diagnose charging system. See appropriate STARTING & CHARGING SYSTEMS article. If voltage reading does not change from zero to 5 volts, go to next step.
- Check generator "L" circuit for open or short to ground. Repair as necessary. After repairs, go to step Β 8. If circuit is okay, go to next step.
- Check generator "L" circuit for short to voltage. Repair as necessary. After repairs, go to step Β 8. If circuit is okay, go to next step.
- Check for poor connection at PCM. Repair as necessary. After repairs, go to step Β 8. If connections are okay, go to next step.
- Replace PCM. program replacement PCM using required equipment. After replacing PCM, go to next step.
- Using scan tool, review and record scan tool FAIL RECORDS data. Clear DTCs. Operate vehicle within conditions for setting this DTC. Recheck DTCs. If this DTC resets, go to step Β 2. If this DTC does not reset, system is okay.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.