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Home › Chevrolet › 2000 › Venture Plus › Repair and Diagnosis › Engine Performance › System › Engine Controls Self-Diagnostics › Diagnostic Tests › DTC P1404: EGR Valve Closed Position Performance › Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC SYSTEM CHECK . After performing OBD system check, go to next step.
    2. NOTE: If DTC P0403 is set, diagnose DTC P0403 first. Go to DTC P0403: EGR SOLENOID CONTROL CIRCUIT .
  2. Start and operate engine at idle. Using scan tool, observe actual EGR position. If actual EGR position is zero percent, go to next step. If actual EGR position is not zero percent, go to step  5.
  3. Turn ignition on, engine off. Using scan tool, select EGR VALVE OUTPUT CONTROL function. Increment EGR valve through all positions while comparing desired to actual EGR position. If desired EGR position remains close to actual EGR position at all commanded positions, go to next step. If desired EGR position does not remain close to actual EGR position, go to step  6.
  4. Using scan tool, review and record FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions. Monitor SPECIFIC DTC INFO for this DTC until this DTC test runs. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan does not indicate that this DTC failed this ignition cycle, see DIAGNOSTIC AIDS .
  5. Disconnect EGR harness connector. Observe actual EGR position on scan tool. If actual EGR position is at zero percent, go to next step. If actual EGR position is not at zero percent, go to step  7.
  6. Using test light connected to battery voltage, probe test light to EGR pintle position sensor ground circuit. If test light illuminates, go to step  9. If test light does not illuminate, go to step  8.
  7. Turn ignition off. Disconnect PCM harness connector. Turn ignition on, engine off. Check voltage between ground and EGR pintle position signal circuit. If voltage reading is zero volts, go to step  12. If voltage reading is not zero volts, go to step  11.
  8. Check EGR pintle position sensor ground circuit for an open between EGR and EGR valve. Repair as necessary. After repairs, go to step  15. If circuit is okay, go to step  13.
  9. Check for poor terminal connections at EGR valve. Repair as necessary. After repairs, go to step  15. If connections are okay, go to next step.
  10. Replace EGR valve. If EGR showed signs of excessive heat, check for restricted exhaust. Exhaust restriction may be caused by faulty injector, grounded injector circuit or faulty PCM. Repair as necessary. Also, check for contaminated oil. After replacing EGR valve, go to step  15.
  11. Locate and repair short to voltage in EGR pintle position signal circuit. After repairs, go to step  15.
  12. Check EGR position signal circuit for short to 5-volt reference circuit or short to control circuit. Repair as necessary. After repairs, go to step  15. If circuits are okay, go to step  14.
  13. Check circuits related to EGR valve for poor terminal connections at PCM. Repair as necessary. After repairs, go to step  15. If connections are okay, go to next step.
  14. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  15. Using scan tool, select CLEAR INFO or CLEAR DTCs function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step  2.
  16. Using scan tool, select CAPTURED INFO feature. If any undiagnosed DTCs are displayed, go to affected DTC test.
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