Circuit/System Testing

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. If any other instrument panel cluster (IPC) indicators or gauges are inoperative, refer to Instrument Cluster Gauges Inoperative .
  2. Ignition OFF, disconnect ECM X1 harness connector. Ignition ON, the MIL should not illuminate.
    • If the MIL is illuminated, test the MIL control circuit terminal X1-68 for a short to ground. If the circuit tests normal, replace the IPC.
  3. Ignition ON, connect a 3 A fused jumper wire between the MIL control circuit terminal X1-68 and ground. The MIL should illuminate.
    • If the MIL does not illuminate, test the MIL control circuit for a short to voltage, or an open/high resistance. If the circuit tests normal, replace the IPC/bulb.
  4. If all circuits/connections test normal, replace the ECM.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.