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Home >> Pontiac >> 2003 >> Aztek AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics >> Diagnostic Tests >> DTC P0141: Ho2S Heater Circuit (Bank 1; Sensor 2) >> Diagnostic Procedures

Diagnostic Procedures

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
    2. NOTE: If engine has just been operating, allow engine to cool until near bias voltage is observed on scan tool before proceeding.
  2. Turn ignition on, with engine off. Monitor HO2S 2 voltage on the scan tool. Does the HO2S 2 voltage go to above or below the previously stabilized voltage, by at least 100 mV within 2 minutes? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. See CONDITIONS FOR RUNNING DTC . Does the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L AZTEK & RENDEZVOUS article.
    4. NOTE: The test light must be connected to a known-good ground. DO NOT use HO2S 2 low signal circuit.
  4. Turn ignition off. Disconnect the HO2S 2 electrical connector. Turn ignition on, with engine off. Connect a test light between the HO2S 2 heater ignition voltage circuit, in the harness side of the HO2S connector, and ground. Does the test light illuminate? If yes, go to next step. If no, go to step  7.
  5. Turn ignition off. Connect a test light between the HO2S 2 heater ignition voltage circuit, in the harness side of the HO2S connector, and the HO2S 2 heater ground circuit. Turn ignition on, with engine off. Does the test light illuminate? If yes, go to step  7. If no, go to step  10.
  6. Test the HO2S 2 heater ignition voltage circuit fuse for an open. Did you find an open fuse? If yes, go to step  8. If no, go to step  9.
  7. Test for an intermittent and for a poor connection at the HO2S 2 harness connector. Did you find and correct the condition? If yes, go to step  12. If no, go to step  11.
  8. Repair short to ground in the HO2S 2 heater ignition voltage circuit and replace the fuse. After repairs, go to step  12.
  9. Repair open or high resistance condition in the HO2S 2 heater ignition voltage circuit. After repairs, go to step  12.
  10. Repair open or high resistance condition in the HO2S 2 heater ground circuit. After repairs, go to step  12.
  11. Replace HO2S 2. See REMOVAL & INSTALLATION - AZTEC & RENDEZVOUS article. After repairs, go to next step.
  12. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running DTC. See CONDITIONS FOR RUNNING DTC . Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  13. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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