Diagnostic Aids: Notes

2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Notes
WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

Important:Β 

  • Do not clear the DTC unless directed by a diagnostic procedure. Clearing the DTCs will erase all Freeze Frame and Failure Records stored in PCM memory.
  • Poor engine performance can sometimes be diagnosed as a rear axle driveability condition. In order to avoid mis-diagnosis of the rear axle, always perform DIAGNOSTIC STARTING POINT -- ENGINE CONTROLS .
  • Use a scan tool that is known to function correctly. If necessary, test the scan tool on another vehicle.
  • Ensure the scan tool contains the most current file available.
  • The scan tool will display a loss of communication error message under the following conditions:
  • The PCM power is interrupted.
  • The ignition switch is turned OFF.
  • The battery voltage level is very low.
  • A poor connection at the diagnostic link connector (DLC).
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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.