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Home >> GMC >> 2002 >> Jimmy 2D Utility, Automatic, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 4.3L >> Diagnostic Tests >> DTC P0135, P0141 & P0155: Ho2S Heater Circuit - Bank 1 & 2, Sensors 1 & 2 (Astro & Safari) >> 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: Allow the engine to cool for one-half hour before proceeding with this diagnostic. This allows the HO2S signal voltage to return to bias voltage, approximately 447 mV.
  2. If DTC P0300 is also set, diagnose P0300 first. See DTC P0300: ENGINE MISFIRE DETECTED . Turn OFF the ignition. Install a scan tool. Turn ON the ignition, with the engine OFF. Immediately observe the affected HO2S voltage for 2 minutes. Does the HO2S voltage go from bias voltage to more than or less than 300-600 mV? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Is the ENG 1 fuse open? If yes, go to step  7. If no, go to next step.
  5. Turn OFF the ignition. Disconnect the affected HO2S connector. Turn ON the ignition, with the engine OFF. Probe the HO2S ignition 1 voltage circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step  11.
  6. Connect a test lamp between the affected HO2S ignition 1 voltage circuit and the HO2S heater ground circuit. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate? If yes, go to step  10. If no, go to step  12.
  7. Disconnect all three HO2S pigtail connectors. Test the HO2S ignition 1 voltage circuit for a short to ground. Replace the ENG 1 fuse. Did you find and correct a short to ground in the ignition 1 voltage circuit? If yes, go to step  14. If no, go to next step.
    8. NOTE: Perform the following test on HO2S bank 1 sensor 1, HO2S bank 2 sensor 1, and HO2S bank 1 sensor 2. A condition in any sensor will cause this DTC to set.
  8. Test the HO2S ignition 1 voltage circuit, sensor side, for a short to the HO2S body. Did you find the condition? If yes, go to step  13. If no, go to next step.
    9. NOTE: Perform the following test on HO2S bank 1 sensor 1, HO2S bank 2 sensor 1, and HO2S bank 1 sensor 2. A condition in any sensor will cause this DTC to set.
  9. Measure the resistance between the HO2S ignition 1 voltage circuit, sensor side, and the HO2S heater ground circuit, sensor side. Does the resistance of any sensor measure above or below 2-50 ohms? If yes, go to step  13. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  10. Inspect for poor connections at the harness connector of the affected HO2S. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  11. Repair the open in the ignition 1 voltage circuit. After repairs, go to step  14.
  12. Repair the open in the HO2S heater ground circuit. After repairs, go to step  14.
  13. Replace the affected HO2S. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to next step.
  14. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  15. 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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