Circuit/System Testing
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- 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 circuit terminals D and F for an open/high resistance, short to voltage, or short to ground. If the circuits test normal, replace the control module.
- After the motor control circuits have tested normal, the component to be replaced is dependant on which DTC is set.
- If DTC P0403 was set, replace the EGR valve motor.
- If DTC P046C was set, replace the EGR valve assembly.