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 1976 (ENGINE COOLING SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC P0480 OR P0481 (LAT)CIRCUIT/SYSTEM TESTING (LAT)
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6
Circuit/System Testing (LAT)
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Testing (LAT)
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the affected relay.
- Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground:
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, replace the relay.
- Test for 70-110 ohms between terminal 85 and terminal 86 of the relay.
- If not within the specified range, replace the relay.
- Test for 0.0A with a DMM connected in series with the relay coil between circuit terminal 85 and circuit terminal 86 at the relay connector.
- If more than the specified value, test the control circuit terminal 86 for a short to ground. If the circuit tests normal, replace the ECM.
- Command the relay ON with a scan tool. Verify that the DMM indicates more than 100 mA.
- If not the specified range, test the control circuit terminal 86 for an open/high resistance. If the circuit tests normal, replace the ECM.
- If all circuits and the ECM test normal, replace the affected relay.
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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.