LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 1998 >> Forward Control P30, 6.5 F, Standard >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 3 (Engine Controls - Tests W/Codes - 5.7L) >> Diagnostic Trouble Codes >> DTC P1404 - EGR Valve Closed Pintle Position >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different variant/trim than selected.
  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step.
  2. Turn ignition on, engine off. Using scan tool, command EGR valve to 20, 50, 70 and 100 percent. If actual EGR position follows commanded EGR position, go to next step. If actual EGR position does not follow commanded EGR position, go to step 4).
  3. DTC is intermittent. Check if additional DTCs are set. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, see DIAGNOSTIC AIDS.
  4. Disconnect EGR harness connector. If actual EGR position is about zero percent, go to step 6). If actual EGR position is not about zero percent, go to next step.
  5. Check EGR valve signal circuit for short to voltage. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to step 14).
  6. Using DVOM, check voltage between ground and EGR 5-volt reference circuit terminal at harness connector. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 8).
  7. Using test light connected to ground, probe test light to EGR valve feed control circuit terminal at harness connector. If test light illuminates, go to step 9). If test light does not illuminate, go to step 10).
  8. Check EGR 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to step 14).
  9. Check EGR feed circuit for short to voltage. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to step 14).
  10. Using test light connected to battery voltage, probe EGR valve ground circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 12).
  11. Check EGR valve ground circuit terminal for poor connection at EGR harness connector. Repair as necessary. After repairs, go to step 16). If connection is okay, go to step 13).
  12. Check for open EGR valve ground circuit. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to step 14).
  13. Replace EGR valve. After replacing EGR valve, go to step 16).
  14. Check for poor connection at VCM harness connector. Repair as necessary. After repairs, go to step 16). If VCM harness connector is okay, go to next step.
  15. Replace VCM. Program replacement VCM using required equipment. After replacing VCM, go to next step.
  16. 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).
  17. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time. See DIAGNOSTIC AIDS.
scientia non olet · About LEMON Manuals