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.
Circuit/System Verification
2008 Pontiac Grand Prix BaseSECTION Circuit/System Verification
WARNING: This page is about a different car, the 2008 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition ON, transmission in Park or Neutral. Observe the PNP Switch parameter with a scan tool, in Engine Control Module, Data Display, Engine Data. Verify that the scan tool PNP Switch parameter is Park/Neutral.
- If the scan tool PNP Switch parameter is not Park/Neutral, refer to Circuit/System Testing PNP Switch Circuit Malfunction.
- Command the Starter Relay ON with the scan tool, or turn the ignition switch to the START position. The starter solenoid should engage and the engine should crank.
- If the solenoid does not engage, refer to Circuit/System Testing STRTR Relay Circuit Malfunction.
- If the solenoid engages but the engine does not crank, refer to Starter Solenoid Clicks, Engine Does Not Crank .
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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.