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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 347 (Engine Controls Self-Diagnostics - 2.2L Bi-Fuel) >> Diagnostic Tests >> DTC P2668: Fuel Indicator Light Command/Actual State Do Not Match >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Chevrolet Cavalier. 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 (Alternative Fuels). If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS (ALTERNATIVE FUELS)  under SELF-DIAGNOSTIC SYSTEM.
  2. Turn ignition switch to RUN position, engine OFF. Command the FIL ON and OFF using a scan tool. Does the FIL respond to the scan tool commands? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Turn ignition switch to RUN position, engine OFF. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING THE DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to INTERMITTENTS in TROUBLE SHOOTING - 2.2L CAVALIER - BI-FUEL - CNG/GASOLINE article.
  4. Turn ignition switch to RUN position. Remove the Fuel Gage Select Switch. See FUEL GAUGE SELECT SWITCH under FUEL SYSTEMS (CNG) in REMOVAL & INSTALLATION - CAVALIER & SUNFIRE article. Turn ignition switch to RUN position, engine OFF. Probe the FIL ignition voltage circuit using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  11.
  5. Connect a test light between the FIL control circuit and the FIL ignition voltage circuit. Command the FIL ON and OFF with a scan tool. Does the test light turn ON and OFF with each command? If yes, go to step  9. If no, go to next step.
  6. Does the test light remain illuminated with each command? If yes, go to step  8. If no, go to next step.
  7. Check the FIL control circuit for an open or for a short to voltage. Did you find and correct the condition? If yes, go to step  14. If no, go to step  10.
  8. Check the FIL control circuit for a short to ground. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  9. Inspect for poor connections at the Fuel Gage Select Switch. Did you find and correct the condition? If yes, go to step  14. If no, go to step  12.
  10. Inspect PCM harness connector for poor connections. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  11. Repair the open or short to ground in the ignition voltage circuit. After repair, go to step  14.
  12. Replace the Fuel Gage Select Switch. See FUEL GAUGE SELECT SWITCH under FUEL SYSTEMS (CNG) in REMOVAL & INSTALLATION - CAVALIER & SUNFIRE article. After repair, go to step  14.
  13. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - CAVALIER & SUNFIRE article. Program PCM with correct vehicle software and calibration. After repair, go to next step.
  14. Clear the DTCs using a scan tool. Turn ignition switch to OFF position for 30 seconds. Turn ignition switch to RUN position, engine OFF. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING THE DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  15. Observe the CAPTURE INFO using a scan tool. Are there any DTCs that have not been diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay at this time.
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