Diagnostic Procedures

2001 Chevrolet Chevy Express G3500, Van Passenger Extended, 6.5 FSECTION Diagnostic Procedures
WARNING: This page is about a different variant/trim than selected.
  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECKΒ  under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
  2. NOTE: If you can hear an engine knock, repair engine mechanical problem before proceeding with this diagnostic.
  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 AIDSΒ .
  4. Replace PCM. Program PCM. See POWERTRAIN CONTROL MODULEΒ  under PROGRAMMING. After repairs, go to next step.
  5. 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 Β 2.
  6. Using scan tool, observe stored information. If scan tool displays any DTCs that have not been diagnosed, see DIAGNOSTIC TROUBLE CODE DEFINITIONSΒ . 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:

  • 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.