Diagnostic Procedures

2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Diagnostic Procedures
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition on, with engine off. Using scan tool, monitor CALC COMPRESSION OUTPUT while cranking engine. Observe scan tool display pattern. If pattern 00000011 or 00001100 is displayed, IC 1/4 circuit is affected. If pattern 00001110 or 00000001 is displayed, IC 2/3 circuit is affected. To diagnose affected circuits, go to step Β 3 . If pattern 00000000 is displayed, go to next step.
  2. NOTE: If a specific cylinder misfire exists and if engine is flooded, refer to DTC P0300 for a CALC COMPRESSION OUTPUT pattern breakdown. Refer to DTC P0300: ENGINE MISFIRE DETECTED in SELF-DIAGNOSTICS - 2.2L VUE article.
  3. Turn ignition off. Remove EI module from ignition coil housing. Remove interconnect from EI module. Turn ignition on, with engine off. Using a test light connected to ground, probe test light between primary ignition coil voltage terminal "D". See Fig 1 . If test light illuminates, check interconnect for tightness. Repair as necessary. If interconnect is okay, replace ignition coil housing. If test light does not illuminate, replace EI module.
  4. Turn ignition off. Remove EI module from ignition coil housing. Ensure EI module interconnect is tight. Connect a Noid Light (J34730-2A) between primary ignition voltage terminal "D" and 1/4 coil control circuit terminal "E" or 2/3 coil control circuit terminal "C". See Fig 1 . Crank engine. If noid light pulses, check terminal tightness in interconnect to ignition coil housing. Repair as necessary. If terminals are okay, replace ignition coil housing. If noid light does not pulse, go to next step.
    Fig 1: Identifying Electronic Ignition Module Terminals (2.2L)
    G00169511Courtesy of GENERAL MOTORS CORP.
  5. Turn ignition off. Leave noid light connected. Disconnect ECM harness connector J2. Turn ignition on, with engine off. Using a test light connected to battery voltage, touch test light to ECM harness connector J2 terminal No. 56 (Orange wire) or terminal No. 27 (White wire) for one second. See Figure . If noid light illuminates when circuit is connected to battery voltage, check for terminal tightness. Repair as necessary. If terminals are okay, replace ECM. If noid light does not illuminate, go to next step.
  6. Turn ignition off. check continuity of Orange or White wire between ECM and EI module harness connectors. See Figure . If continuity exists, go to next step. If continuity does not exist, repair open in circuit.
  7. Check continuity of Orange or White wire to ground at EI module harness connector. If continuity exists, repair grounded circuit. If continuity does not exist, go to next step.
  8. Turn ignition off. Reconnect ECM harness connector. Turn ignition on, with engine off. Check voltage between ground and ECM harness connector J2 terminals No. 27 (White wire) or No. 56 (Orange wire). See Figure . If voltage is present, repair short to voltage in affected circuits. If voltage is not present, check ECM harness connector tightness. Repair as necessary. If terminals are okay, replace EI module.
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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.