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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 5 (ENGINE CONTROLS - SELF-DIAGNOSTICS - 8.1L)SELF-DIAGNOSTIC SYSTEMPOWERTRAIN DIAGNOSTIC SYSTEM CHECK
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8

Powertrain Diagnostic System Check

2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Powertrain Diagnostic System Check
WARNING: This page is about a different variant/trim than selected.

The powertrain diagnostic system check determines:

  • Identification of control modules which command the system.
  • Ability of control modules to communicate through serial data circuit.
  • Identification and status of any stored DTCs.

NOTE: Check for applicable Technical Service Bulletins (TSB) before proceeding. DO NOT perform the following procedure if driveability conditions are not present, unless another procedure directs you here. DO NOT turn ignition off during the following procedure or clear DTCs unless instructed to do so. Tech 2 scan tool or other OBD-II compatible scan tool is required to perform powertrain diagnostic system check.
  1. If vehicle does not crank, see appropriate STARTERS article in STARTING & CHARGING SYSTEMS. Ensure battery is fully charged and cables are clean and tight. Ensure PCM grounds are clean, tight, and in proper location. Install scan tool. If scan tool turns on, go to next step. If scan tool does not turn on, see SCAN TOOL DOES NOT POWER UP under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  2. Turn ignition switch to ON position. Attempt to establish communication with Electronic Brake Control Module (EBCM), Instrument Panel Cluster (IPC), PCM, Heating Ventilation/Air Conditioning (HVAC) and Vehicle Theft Deterrent (VTD) module. If scan tool communicates with all control modules, go to next step. If scan tool does not communicate with all control modules, see SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  3. Attempt to start engine. If engine starts and idles, go to next step. If engine does not start and idle, see appropriate BASIC DIAGNOSTIC PROCEDURES article.
  4. Select DTC display function for EBCM, IPC, PCM, HVAC and VTD. If DTCs exist, go to next step. If DTCs do not exist, go to step  8.
  5. Using scan tool, select CAPTURED INFORMATION to store powertrain DTC information. Go to next step.
  6. If scan tool displays any DTCs which begin with "U" (communication DTCs), see SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display any DTCs which begin with "U", go to next step.
  7. If scan tool displays any DTCs which begin with "P", perform appropriate test. Go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not display any DTCs which begin with "P", go to next step.
  8. If customer's concern is with the automatic transmission, see appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS. If customer's concern is not with the automatic transmission, go to next step.
  9. If customer's concern is with Inspection/Maintenance (I/M) testing, go to INSPECTION/MAINTENANCE SYSTEM CHECK  under INSPECTION/MAINTENANCE PROCEDURES. If customer's concern is not with I/M testing, go to next step.
  10. Repair as necessary. See appropriate SYSTEM & COMPONENT TESTING article.
RENDER: 1.0x

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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.