LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Pontiac >> 2001 >> Aztek Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics >> Diagnostic Tests >> DTC P1404: EGR Valve Closed Position Performance >> Diagnostic Procedures
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedures

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
  2. If DTC P0403 is set, diagnose DTC P0403 first. See DTC P0403 . Using scan tool, observe EGR position sensor parameter. If EGR position sensor parameter is at zero percent, go to next step. If EGR position sensor parameter is not at zero percent, go to step  5.
  3. Turn ignition on, with engine off. Using scan tool, command EGR valve from 0-100 percent. If desired EGR position remains within 15 percent of EGR position sensor at all commanded positions, go to next step. If desired EGR position does not remain within 15 percent of EGR position sensor at all commanded positions, go to step  6.
  4. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See CODE ENABLE CRITERIA . If DTC fails this ignition, go to next step. If DTC does not fail this ignition, see DIAGNOSTIC AIDS .
  5. Turn ignition off. Disconnect EGR valve harness connector. Turn ignition on, with engine off. Using scan tool, observe EGR position sensor parameter. If EGR position sensor is at zero percent, go to next step. If EGR position sensor is not at zero percent, go to step  9.
  6. Using a DVOM, check voltage between EGR harness connector terminals "B" (Black wire) and "D" (Gray wire). See Figure. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step  8.
  7. Connect a fused jumper wire between EGR harness connector terminals "C" (Brown wire) and "D" (Gray wire). If scan tool indicates that EGR position sensor value is about 100 percent, go to step  13. If scan tool does not indicate that EGR position sensor value is about 100 percent, go to step  11.
  8. Check voltage between ground and EGR harness connector terminal "D" (Gray wire). If voltage reading is about 5 volts, go to step  10. If voltage reading is not about 5 volts, go to step  12.
  9. Turn ignition off. Check for short to voltage in Brown wire between EGR harness connector terminal "C" and PCM harness connector C2 terminal No. 28. Repair as necessary. After repairs, go to step  17. If circuit is okay, go to step  14.
  10. Turn ignition off. Check for open or high resistance in Black wire between EGR harness connector terminal "B" and PCM harness connector C1 terminal No. 31. Repair as necessary. After repairs, go to step  17. If circuit is okay, go to step  14.
  11. Turn ignition off. Check for high resistance or short to ground in Brown wire between EGR harness connector terminal "C" and PCM harness connector C2 terminal No. 28. Repair as necessary. After repairs, go to step  17. If circuit is okay, go to step  14.
  12. Turn ignition off. Check for open, short to ground, or short to voltage in Gray wire between EGR harness connector terminal "D" and PCM harness connector C2 terminal No. 30. Repair as necessary. After repairs, go to step  17. If circuit is okay, go to step  14.
  13. Turn ignition off. Check for poor connections at EGR valve harness connector. Repair as necessary. After repairs, go to step  17. If connections are okay, go to step  15.
  14. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step  17. If connections are okay, go to step  16.
  15. Replace EGR valve. After replacing EGR valve, go to step  17.
  16. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  17. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See CODE ENABLE CRITERIA . If DTC runs and passes, go to next step. If DTC resets, go to step  2.
  18. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displayed any undiagnosed DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are displayed, system is okay.
scientia non olet · About LEMON Manuals