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 2008 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition ON, disconnect the battery current sensor.
- Measure the voltage of the 5 volt reference circuit terminal A. Verify that the 5 volt reference circuit measures 5 volts.
- If the voltage is less than 5 volts, test the current sensor 5 volt reference circuit for a short to ground, a high resistance, or an open circuit. If the circuit tests normal, replace the BCM.
- Measure the voltage of the between the 5-volt reference circuit terminal A and the low reference circuit terminal B. Verify that there is 5 volts between the 5-volt reference circuit and the low reference circuit.
- If the voltage is less than 5 volts, test the current sensor low reference circuit for a high resistance, or an open circuit. If the circuit tests normal, replace the BCM.
- Measure the voltage of the signal circuit terminal C. Verify that the signal circuit measures 4-6 volts.
- If the signal circuit voltage is less than 4 volts, test the current sensor signal circuit for a short to ground, a high resistance, or an open circuit. If the circuit tests normal, replace the BCM.
- If the signal circuit voltage is greater than 6 volts, test the current sensor signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
- If all 3 circuits test normal, replace the battery current sensor.
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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.