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Home >> Cadillac >> 1998 >> Catera >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0411 - Air System No Flow Detected >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  , then go to next step.
  2. Turn ignition on, with engine off. Using scan tool, command AIR pump relay on and off. If AIR pump turns on and off, go to step 10). If AIR pump does not turn on and off, go to next step.
  3. Turn ignition off. Disconnect AIR pump relay connector. Turn ignition on, with engine off. Using test light connected to ground, probe relay battery supply circuit. If test light is on, go to next step. If test light is off, go to step 16).
  4. Using test light connected to ground, probe relay switched battery feed circuit. If test light is on, go to next step. If test light is off, go to step 17).
  5. Using test light connected to battery voltage, probe relay control circuit. Using scan tool, command AIR pump relay on and off. If test light turns on and off, go to next step. If test light does not turn on and off, go to step 9).
  6. Using a fused jumper wire, jumper battery feed circuit to AIR pump feed circuit at relay connector. If AIR pump turns on, go to step 25). If AIR pump does not turn on, go to next step.
  7. Leave fused jumper connected. Disconnect electrical connector from AIR pump. Using test light connected to ground, probe AIR pump harness connector feed circuit. If test light is on, go to next step. If test light is off, go to step 18).
  8. Using test light connected to battery voltage, probe AIR pump harness connector ground circuit. If test light is on, go to step 27). If test light is off, go to step 19).
  9. Turn ignition off. Disconnect ECM harness connector located in engine compartment relay center. Using DVOM, check harness continuity of control circuit. If continuity is present, go to step 29). If continuity is not present, go to step 20).
  10. Start engine. Disconnect vacuum hose from cutoff valve. Using scan tool, command AIR solenoid valve on. If vacuum is present at cutoff valve, go to step 13). If vacuum is not present at cutoff valve, go to next step.
  11. Disconnect manifold vacuum supply hose at AIR solenoid valve. If manifold vacuum is present at solenoid valve, go to next step. If manifold vacuum is not present at solenoid valve, go to step 21).
  12. Reconnect vacuum supply hose, and disconnect hose to cutoff valve at solenoid valve. Connect the 2 hoses together using suitable coupler. If vacuum is present at cutoff valve, go to step 23). If vacuum is not present at cutoff valve, go to step 22).
  13. Remove cutoff valve. Using a hand held vacuum pump, apply vacuum to valve and attempt to blow through valve. If valve is open, go to next step. If valve is not open, go to step 24).
  14. Disconnect AIR pump outlet hose. Using scan tool, command AIR pump relay on and off. If air is present at AIR pump outlet when pump is running, go to next step. If air is not present at AIR pump outlet when pump is running, go to step 28).
  15. Check for damaged or blocked AIR hoses and pipes between AIR pump and engine. Repair as necessary. After repairs, go to step 31).
  16. Repair battery supply circuit to relay. After repairs, go to step 31).
  17. Repair switched battery feed circuit to relay. After repairs, go to step 31).
  18. Repair AIR pump feed circuit between AIR pump and AIR pump relay. After repairs, go to step 31).
  19. Repair open or high resistance in AIR pump ground circuit. After repairs, go to step 31).
  20. Repair open or high resistance in relay control circuit. After repairs, go to step 31).
  21. Repair vacuum supply hose or plugged vacuum source. After repairs, go to step 31).
  22. Repair vacuum hose to cutoff valve. After repairs, go to step 31).
  23. Replace solenoid valve. After replacing valve, go to step 31).
  24. Replace AIR cutoff valve. After replacing valve, go to step 31).
  25. Check for poor connections and terminal tension at relay harness connector. Repair as necessary. After repairs, go to step 31). If connections and terminals are okay, go to next step.
  26. Replace relay. After replacing relay, go to step 31).
  27. Check for poor connections and terminal tension at AIR pump harness connector. Repair as necessary. After repairs, go to step 31). If connections and terminals are okay, go to next step.
  28. Replace AIR pump. After replacing AIR pump, go to step 31).
  29. Check for poor connections and terminal tension at ECM harness connector. Repair as necessary. After repairs, go to step 31). If connections and terminals are okay, go to next step.
  30. Replace ECM. New ECM must be programmed with theft deterrent module frequency code currently on vehicle. After replacing ECM, go to next step.
  31. Using scan tool, clear DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle. Check for DTCs. If DTC P0411 is set, repeat step 2). If DTC P0411 is not set, go to next step.
  32. If other DTCs were present during OBD system check and have not been diagnosed, go to applicable DTC. If no other DTCs are present, system is okay.
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