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 MANUALSCHEVROLET2006CHEVY EXPRESS G2500, VAN CARGO, 6.6 2REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 960 (ENGINE CONTROL SYSTEM & FUEL SYSTEM - 6.6L (LLY) - DTC P0401 TO DTC P2510)DTC P0403CIRCUIT/SYSTEM TESTING
2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2
Circuit/System Testing
2006 Chevrolet Chevy Express G2500, Van Cargo, 6.6 2SECTION Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2007 GMC Savana Special, 2007 GMC Savana Camper Special, 2007 GMC Savana, 2007 Chevrolet RV Cutaway, and 2007 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
Perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Capture the information and clear the DTCs with a scan tool.
- Turn OFF the ignition. Disconnect the EGR valve. Install the EN-48565 between the EGR valve and the harness connector. See Special Tools .
- Turn ON the ignition. Command the EGR valve to 50 percent and back to 0 percent. The EGR test harness lamp should turn ON between 10 percent and 50 percent, and turn OFF at 0 percent.
- If the lamp does not turn ON and OFF, test both motor control circuits for an open/high resistance, short to voltage, or short to ground. If the circuits test normal, replace the control module.
- If the lamp turns ON and OFF, replace the EGR valve.
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.