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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 123 (Engine Controls - Self-Diagnostics - 4.0L) >> Diagnostic Tests >> DTC P0155: Ho2S Bank 2 Sensor 1 Circuit - Heater Performance >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. 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, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Turn ON the ignition, with the engine OFF. With a scan tool, clear the DTCs. With a scan tool, observe the DTC information for 30 seconds. Are DTCs P0030, P1031, and P1032 set? If yes, see DTC P0030: HO2S HEATER CONTROL CIRCUIT (SENSOR 1) . If no, go to next step.
  3. Start the engine. With a scan tool, observe the DTC information for 5 minutes. Are DTCs P0135 and P0155 set? If yes, see DTC P0135: HO2S BANK 1 SENSOR 1 - HEATER PERFORMANCE . 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. Turn OFF the ignition. Disconnect the HO2S bank 2 sensor 1 harness connector. Test the ignition 1 voltage circuit of the HO2S bank 2 sensor 1 heater for an open. Did you find and correct the condition? If yes, go to step  12. If no, go to next step.
    6. WARNING: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.
  6. Turn OFF the ignition. Disconnect the HO2S bank 2 sensor 1 harness connector. Turn ON the ignition, with the engine OFF. With a DMM, measure the voltage at the HO2S bank 2 sensor 1 heater low control circuit. Does the voltage measure near 5 V? If yes, go to step  8. If no, go to next step.
  7. Turn OFF the ignition. Disconnect the PCM harness connector. Test the HO2S bank 2 sensor 1 heater low control circuit for the following conditions:
    • An open circuit.
    • A short to ground.
    • A short to the HO2S low signal.

    Did you find and correct the condition? If yes, go to step  12. If no, go to step  9.

  8. Inspect for poor connections at the harness connector of the HO2S bank 2 sensor 1. Did you find and correct the condition? If yes, go to step  12. If no, go to step  10.
  9. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step  12. If no, go to step  11.
  10. Replace HO2S bank 2 sensor 1. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  12.
  11. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  12. Use the scan tool in order to clear the DTCs. 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.
  13. With a scan tool, observe the stored information, 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.
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