Diagnostic Procedures

2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Diagnostic Procedures
WARNING: This page is about a different variant/trim than selected.
  1. Perform the I/M system check. See INSPECTION/MAINTENANCE SYSTEM CHECK . After performing I/M system check, go to next step.
  2. Ensure engine coolant temperature is 133-219°F (56-104°C). Set parking brake. Ensure transmission is in Park (A/T) or Neutral (M/T). Turn all of accessories off (e.g. A/C, blower fan, etc.). Start and operate engine at idle. Allow engine to idle for 2 minutes or until I/M System Status indicator updates to YES. If status updates to YES, go to step  5. If status does not update to YES, go to next step.
  3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not indicate any failed DTCs, go to next step.
  4. Using scan tool, observe the NOT RAN SINCE CODE CLEARED display. Determine which of the DTCs required for a YES status has not run. Enter DTC number in the Specific DTC menu of scan tool. Ensure engine coolant temperature is 133-219°F (56-104°C). Repeat procedure until scan tool indicates that diagnostic test has run. Repeat this step or any additional required DTCs that have not run. Observe I/M System Status display on scan tool. If Misfire Monitoring System Status updates to YES, go to next step. If Misfire Monitoring System Status does not update to YES, see DIAGNOSTIC AIDS .
  5. Using scan tool, observe emission related DTC portion of I/M System Status display. If scan tool indicates any emission related DTCs, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not indicate emission related 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.