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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 405 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0155: Ho2S Bank 2, Sensor 1 Heater Circuit >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Cadillac Seville and 2003 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
  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. Turn ignition on, with engine off. Clear the DTCs with a scan tool. Observe the DTC information with a scan tool for at least 30 seconds. Did DTCs P0030, P1031, and P1032 fail this ignition cycle? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  3. Start the engine. Observe the DTC information with a scan tool for at least 5 minutes. Did DTCs P0135 and P0155 fail this ignition cycle? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  4. Is DTC P0155 set? If yes, go to next step. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
    5. NOTE: Use a known good ground. Do not use the Heated Oxygen Sensor (HO2S) heater low control circuit or the HO2S low signal circuit.
  5. Turn ignition off. Disconnect the Heated Oxygen Sensor (HO2S) bank 2 sensor 1 harness connector. Probe the HO2S bank 2 sensor 1 heater ignition 1 voltage circuit at the engine harness side of the HO2S connector with a test light that is connected to a good ground. Turn ON the ignition, with the engine OFF. Does the test light illuminate? If yes, go to next step. If no, go to step  7.
  6. Turn ignition on, with engine off. Measure the voltage at the HO2S bank 2 sensor 1 heater low control circuit of the HO2S harness connector, on the engine harness side, to a good ground. Is the voltage 4-6 volts? If yes, go to step  9. If no, go to step  8.
  7. Test the HO2S bank 2 sensor heater ignition 1 voltage circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  13.
  8. Test the HO2S bank 2 sensor 1 heater low control circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  13. If no, go to step  10.
  9. Test for an intermittent and/or poor connections at the HO2S bank 2 sensor 1. Did you find and correct the condition? If yes, go to step  13. If no, go to step  11.
  10. Test for an intermittent and/or poor connections at the PCM. Did you find and correct the condition? If yes, go to step  13. If no, go to step  12.
  11. Replace HO2S bank 2 sensor 1. See HEATED OXYGEN SENSOR under SENSORS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you complete the replacement? If yes, go to step  13.
  12. Replace PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you complete the replacement? If yes, go to next step.
  13. Clear the DTCs with a scan tool. Turn off the ignition for 30 seconds. Start the engine and operate vehicle within the Conditions For Running DTC. You may also operate vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to step  2. If no, go to next step.
  14. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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