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 Testing
2008 Pontiac Grand Prix BaseSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2007 Buick LaCrosse and 2007 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
- The PPS module
- The SDM module
- The PPS wiring harness connector
- The SDM wiring harness connector
- Ignition ON, the PPS should turn ON the PPS ON/OFF indicators. Verify the PPS illuminates the PPS ON/OFF indicators.
- If the Passenger Air Bag ON/OFF status indicator does not illuminate refer to Passenger Presence System Indicator Circuit Malfunction .
- Ignition ON, use the scan tool. Go to the PPS menu, then retrieve the DTCs. Refer to Passenger Presence System Flash Code Procedures . Verify no PPS DTCs are set.
- If the PPS has any current or history DTCs stored, you must address the PPS DTCs first. Refer to the Diagnostic Trouble Code (DTC) List - Vehicle .
- Ignition OFF, disconnect the PPS module connector. Note: Refer to Passenger Presence System (PPS) Replacement in Repair Instructions for connector location.
- Remove the SDM connector, refer to Inflatable Restraint Sensing and Diagnostic Module Replacement in Repair Instructions for connector location.
- Test the occupant sensor serial data circuit for an open, short to ground, or high resistance between the PPS and SDM connector. Verify no open, short to ground, or high resistance exists.
- If any of the above conditions are found make the appropriate repair.
- Test the PPS ignition 1 voltage and ground circuits for a short to ground, a short to voltage, a high resistance, or an open. Verify no short to ground, a short to voltage, a high resistance, or an open exists.
- If any of the above conditions are found make the appropriate repair.
- If all circuits test normal then replace the PPS.
IMPORTANT:
When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.
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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.