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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1375 (Engine Controls And Fuel - 6.6L - DTC P02E8 To DTC P1247) >> DTC P0401 or P0402 >> Component Testing

Component Testing

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: Perform the Circuit/System Testing before proceeding with the Component Testing.
  1. Remove the EGR valve. Refer to Exhaust Gas Recirculation Valve Replacement .
  2. Inspect the EGR valve, the EGR cooler, the air inlet tube, and all of the EGR passages for the following conditions:
    • A sticking, binding, or frozen EGR valve
    • A leak or restriction in the EGR valve and EGR ports and passages
    • Any coking, soot build up, debris, damage, that can cause the EGR valve to stick partially open or closed