LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 92 (Engine Controls - Self-Diagnostics - 6.6L Diesel) >> Diagnostic Tests >> DTC P0612: Fuel Injection Control Module Internal Fault >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Attempt to start the engine. Does the engine start? If yes, see DIAGNOSTIC AIDS . If no, go to next step.
  3. Turn OFF the ignition. Remove the ignition 1 relay using J 43244 Relay Puller Pliers. Disconnect the ECM connector containing the ignition 1 relay control circuit. Turn ON the ignition. Probe the ignition 1 relay control circuit with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to step  5. If no, go to next step.
  4. Using a Digital Multimeter (DMM), measure the resistance of the coil circuit of the ignition 1 relay. Does the resistance measure 60-80 ohms? If yes, go to step  7. If no, go to step  6.
  5. Repair the short to battery or ignition voltage on the ignition 1 relay control circuit. After repairs, go to step  8.
  6. Replace the ignition 1 relay. After repairs, go to step  8.
  7. Replace the ECM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram ECM. See ENGINE CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  8. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  9. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
scientia non olet · About LEMON Manuals