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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 250 (Engine Controls Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0141: Ho2S Heater Performance - Sensor 2 >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
  2. Turn ignition switch to RUN position, engine OFF. Using the scan tool, command the HO2S 2 heater ON. Wait 15 seconds to allow the HO2S 2 heater current to stabilize. Observe the HO2S 2 heater current parameter. Is the HO2S 2 heater current parameter 0.217-1056 amps? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
  4. Inspect the O2 HTR fuse (Cavalier & Sunfire) or ERLS fuse (Alero & Grand Am). Is the O2 HTR or ERLS fuse open? If yes, go to next step. If no, go to step  6.
  5. Check the ignition 3 voltage circuit for a short to ground. Did you find and correct the condition? If yes, go to step  20. If no, go to step  8.
  6. Disconnect the HO2S 2 harness connector. Turn ignition switch to RUN position, engine off. Probe the ignition 3 voltage circuit of the HO2S harness connector on the engine harness side using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  17.
  7. Connect a test light between the ignition 1 voltage circuit of the HO2S harness connector on the engine harness side and the HO2S heater low control circuit of the HO2S harness connector on the engine harness side. Command the HO2S 2 heater ON and OFF using a scan tool. Does the test light turn ON and OFF with each command? If yes, go to step  9. If no, go to step  10.
  8. Check the ignition 3 voltage circuit on the sensor side of the HO2S connector for a short to ground. Is the sensor shorted to ground? If yes, go to step  18. If no, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
  9. Measure the resistance of the following circuits using a DMM:
    • HO2S heater low control circuit.
    • Ignition 3 voltage circuit.

    Is the resistance of either circuit more than 3 ohms? If yes, go to step  16. If no, go to step  14.

  10. Does the test light remain illuminated with each command? If yes, go to next step. If no, go to step  12.
  11. Check the HO2S heater low control circuit for a short to ground. Did you find and correct the condition? If yes, go to step  20. If no, go to step  15.
  12. Check the HO2S heater low control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  20. If no, go to next step.
  13. Check the HO2S heater low control circuit for an open. Did you find and correct the condition? If yes, go to step  20. If no, go to step  15.
  14. Check for an intermittent and for a poor connection at the HO2S. Did you find and correct the condition? If yes, go to step  20. If no, go to step  19.
  15. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step  20. If no, go to step  19.
  16. Repair the circuit with high resistance. After repair, go to step  20.
  17. Repair the open in the ignition 3 voltage circuit. After repair, go to step  20.
  18. Replace the HO2S 2. After repair, go to step  20.
  19. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE REPROGRAMMING  under PROGRAMMING. After replacing PCM, go to next step.
  20. Were you sent to this diagnostic from DTC P0140? If yes, go to step  18 in DTC P0140: HO2S 2 CIRCUIT - INSUFFICIENT ACTIVITY - SENSOR 2. If no, go to next step.
  21. Replace the O2 HTR fuse (Cavalier & Sunfire) or ERLS fuse (Alero & Grand Am) if necessary. Using a scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  22. Using the scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay at this time.
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