Diagnostic Procedures

2001 Chevrolet Chevy Express G1500, Van Cargo, 5.0 MSECTION Diagnostic Procedures
  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK . After performing powertrain diagnostic system check, go to next step.
  2. Verify whether Instrument Panel (IP) is operational. If IP is completely inoperative, see appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Turn ignition on, engine off. Using scan tool, command MIL on and off. Repeat commands as necessary. If MIL turns on and off when commanded, go to next step. If MIL does not turn on and off when commanded, go to step  4.
  3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME/FAILURE RECORDS data as possible. If DTC failed this ignition cycle, go to next step. If DTC did not fail this ignition cycle, see DIAGNOSTIC AIDS .
  4. Inspect GAUGES fuse (10-amp). Gauges fuse is located in instrument panel fuse block. If GAUGES fuse is open, go to step  10. If fuse is not open, go to next step.
  5. Turn ignition off. Disconnect PCM. Turn ignition on. If MIL is off, go to next step. If MIL is not off, go to step  11.
  6. Turn ignition off. Remove GAUGES fuse (10-amp) form instrument panel fuse block. Turn ignition on, engine off. Connect a DVOM between PCM Red connector C2 terminal No. 46 (Brown/White wire) and ground. See Figure. If voltage is zero volts, go to next step. If voltage is not zero volts, go to step  12.
  7. Turn ignition off. Reinstall Gauges fuse. Turn ignition on, engine off. Connect a fused jumper wire between PCM Red connector C2 terminal No. 46 (Brown/White wire) and ground. If MIL is on, go to step  15. If MIL is off, go to next step.
  8. Turn ignition off. Remove IP. Turn ignition on, engine off. Using a test light connected to ground, probe IP connector terminal B17 (Pink wire). See Figure. If test light is on, go to next step. If test light is off, go to step  13.
  9. Check Brown/White wire between IP and PCM for open or high resistance. If problem was found, repair as necessary. After repairs, go to step  18. If problem was not found, go to step  14.
  10. Repair short to ground in Pink wire between fuse block and IP. After repairs, go to step  18.
  11. Repair short to ground in Brown/White wire between IP and PCM. After repairs, go to step  18.
  12. Repair short to voltage in Brown/White wire between IP and PCM. After repairs, go to step  18.
  13. Repair the open in Pink wire between fuse block and IP. After repairs, go to step  18.
  14. Check IP connector for poor connections. If problem was found, repair as necessary. After repairs, go to step  18. If problem was not found, go to step  16.
  15. Check PCM connectors for poor connections. If problem was found, repair as necessary. After repairs, go to step  18. If problem was not found, go to step  17.
  16. Replace IP. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs, go to step  18.
  17. Replace PCM. Program PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  18. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria. If DTC runs and passes, go to next step. If DTC does not run and pass, go to step  2.
  19. Using scan tool, observe stored information. If scan tool displays any DTCs that have not been diagnosed, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not display any DTCs, system is okay.
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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.