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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 393 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P1031: Ho2S Heater Current Monitor Control Circuit Sensors 1 & DTC P1032: Ho2S Heater Warm Up Control Circuit Sensors 1 >> 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 INFO parameter with a scan tool for 30 seconds. Do DTCs P0030, P1031, and P1032 fail this ignition cycle? If yes, see DTC P0030: HO2S HEATER CONTROL CIRCUIT SENSOR 1 . If no, go to next step.
  3. Start the engine. Observe the DTC INFO parameter with a scan tool for at least 30 seconds. Do DTCs P1031 and P1032 set? If yes, go to next step. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn ignition off. Disconnect the Heated Oxygen Sensor (HO2S) bank 1 sensor 1 harness connector. Probe the HO2S bank 1 sensor 1 heater low control circuit with a test light that is connected to battery voltage. Turn ignition on, with engine off. Command the O2S heater driver 3 on and off with a scan tool. Does the test light flash on and off? If yes, go to step  9. If no, go to next step
  5. Turn ignition off. Disconnect the HO2S bank 2 sensor 1 harness connector. Probe the HO2S bank 1 sensor 1 heater low control circuit with a test light that is connected to battery voltage. Command the O2S heater driver 3 on and off with a scan tool. Does the test light flash on and off? If yes, go to step  8. If no, go to next step.
    6. NOTE: Disconnection of the PCM during testing may eliminate the voltage source that caused this fault.
  6. Test the HO2S bank 1 sensor 1 heater low control circuit for a short to voltage, or a short to the HO2S bank 1 sensor 1 heater high control circuit. Did you find and correct the condition? If yes, go to step  14. If no, go to next step.
  7. Test the HO2S bank 2 sensor 1 heater low control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  14. If no, go to step  10.
  8. 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  14. If no, go to step  11.
  9. Test for an intermittent and/or poor connections at the HO2S bank 1 sensor 1. Did you find and correct the condition? If yes, go to step  14. If no, go to step  12.
  10. Test for an intermittent and/or poor connections at the PCM. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  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  14.
  12. Replace HO2S bank 1 sensor 1. See HEATED OXYGEN SENSOR under SENSORS in REMOVAL & INSTALLATION - DEVILLE & SEVILLE article. Did you complete the replacement? If yes, go to step  14.
  13. 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.
  14. 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.
  15. 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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