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.
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6FACTORY OEM SERVICE PROCEDURE
Circuit/System Testing
- Using the DTC Descriptor and Diagnostic Aids determine which module is not communicating.
- Ignition OFF, disconnect the harness connector at the module that is not communicating.
- Test for less than 0.5 ohm between each ground circuit of the module that is not communicating and ground.
- If greater than 0.5 ohm, repair the open/high resistance in the ground circuit.
- Test for battery voltage between each battery positive voltage circuit of the module that is not communicating and ground.
- If less than battery voltage, repair the short to ground or open/high resistance in the battery positive voltage circuit.
- Ignition ON, test for battery voltage between each ignition circuit of the module that is not communicating and ground.
- If less than battery voltage, repair the short to ground or open/high resistance in the ignition circuit.
- Ignition OFF, disconnect the harness connector at the module that reported the no communication DTC.
- Ignition OFF, test for less than 0.5 ohm in each serial data circuit between the module that is not communicating and the module that reported the DTC.
- If greater than 0.5 ohm, repair the open/high resistance in the serial data circuit.
- If all tests normal, replace the module that is not communicating.
Factory Service Tools
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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.
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