ECM/FICM Harness Resistance

2003 GMC Sierra 2500 HD, 2D Pickup, 6.6 1, RWD, StandardSECTION ECM/FICM Harness Resistance

Turn ignition switch to LOCK position. Disconnect ECM/FICM and appropriate component harness connectors. Check for open or short circuits between appropriate ECM/FICM harness connector terminal and appropriate component harness connector terminal. If harness is open or shorted, repair as necessary.

Fig 1: Identifying ECM Connector C1 Terminals (1 Of 3)
G00169566Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

NO RELATED

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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.