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 MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1801 (ENGINE CONTROLS AND FUEL - 4.4L - DTC P0010 TO DTC P0158)DTC P012BCOMPONENT TESTING
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6
Component Testing
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Component Testing
WARNING: This page is about a different car, the 2009 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
You must perform the Circuit/System Testing before proceeding with the Component Testing.
- Ignition OFF, remove the SCIAP sensor.
- Install a 3A fused jumper wire between the 5-volt reference terminal C of the sensor and a 5-volt reference.
- Install a jumper wire between the low reference terminal A of the sensor and ground.
- Install a jumper wire at the signal terminal B of the SCIAP sensor.
- Connect a DMM between the jumper wire from terminal B of the SCIAP sensor and ground.
- Ignition ON, with the J 23738-A: Mityvac or J 35555: Metal Mityvac slowly apply vacuum to the sensor while monitoring the voltage on the DMM. The voltage should vary between 4.9-0.4 volts, without any spikes or dropouts.
- If the voltage is not within the specified range or is erratic, replace the SCIAP sensor.
RENDER: 1.0x
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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.