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 inspection/maintenance system check. See INSPECTION/MAINTENANCE SYSTEM CHECKΒ . After performing inspection/maintenance system check, go to next step.
  2. WARNING: Road test vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.
  3. Ensure vehicle meets the specific conditions under CONDITIONS FOR RUNNINGΒ . Turn off all accessories (e.g., A/C, blower fan, etc.). Start engine and allow to idle for 2 minutes. Accelerate vehicle at part throttle to 45 MPH and maintain speed for one minute. Perform 4 decelerations of 25 seconds each from 45 MPH while maintaining the following criteria:
    • Throttle closed.
    • No brake application.
    • No clutch actuation on M/T.
    • No manual downshift.
    • Vehicle speed remains greater than 25 MPH.
    • After each deceleration period, vehicle is returned to 45 MPH under part throttle acceleration and speed is maintained for 15 seconds.
    Using scan tool, observe I/M SYSTEM STATUS display. If EGR system status updates to YES, go to step Β 5. If EGR system status does not update to YES, go to next step.
  4. Using scan tool, observe DTC INFO. If any DTCs are set, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONSΒ . If no DTCs are set, go to next step.
  5. Using scan tool, observe the NOT RAN SINCE CODE CLEARED display to determine if DTCs P0401, P0404, P0405 and P1404 have run. Determine which of the DTCs required for a YES status have not been run. Enter DTC in SPECIFIC DTC menu on scan tool. Operate vehicle within conditions under CODE ENABLE CRITERIA for the specific DTC to run. Repeat procedure until scan tool indicates the diagnostic test has run. Repeat this step for any additional required DTCs that have not run. Using scan tool, observe I/M SYSTEM STATUS display. If status updates to YES, go next step. If status does not update to YES, see DIAGNOSTIC AIDSΒ .
  6. Using scan tool, observe emission related DTC portion of I/M System Status display. If scan tool indicates any emission related DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONSΒ . If no DTCs are displayed, 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.