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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 P0030: Ho2S Heater Control Circuit (Sensor 1) >> 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, see 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 DTCs P0030, P0036, P1031 and P1032. Are all 4 DTCs set? If yes, go to step  11. If no, go to next step.
  3. Did DTCs P0030, P1031 & P1032 Set? If yes, go to step  7. If no, go to next step.
  4. Is DTC P0030 set? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  5. Turn OFF the ignition. Disconnect the HO2S bank 1 sensor 1 harness connector. Turn ON the ignition, with the engine OFF. With a DMM, measure the voltage at the HO2S bank 1 sensor 1 heater high control circuit. Is the voltage more than 10 V? If yes, go to step  15. If no, go to next step.
  6. Turn OFF the ignition. Disconnect the PCM connector. Test the HO2S bank 1 sensor 1 heater high control circuit for a short to ground or a short to the HO2S low signal circuit. Did you find and correct the condition? If yes, go to step  18. If no, go to step  17.
  7. Turn OFF the ignition. Disconnect the HO2S bank 1 sensor 1 harness connector. Turn ON the ignition, with the engine OFF. With a DMM, measure the voltage at the HO2S bank 1 sensor 1 heater low control circuit. Is the voltage more than 10 V? If yes, go to step  15. If no, go to next step.
    8. WARNING: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.
  8. 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 1 sensor 1 heater low control circuit. Is the voltage 1.2-1.7 V? If yes, go to step  14. If no, go to next step.
  9. Turn OFF the ignition. Disconnect the PCM harness connector. Test the HO2S bank 1 sensor 1 heater low control circuit for a short to ground. Did you find and correct the condition? If yes, go to step  18. If no, go to next step.
  10. Test the HO2S bank 2 sensor 1 heater low control circuit for a short to ground. Did you find and correct the condition? If yes, go to step  18. If no, go to step  17.
  11. Turn OFF the ignition. Remove the HO2S fuse from the underhood electrical center. With a test lamp connected to battery voltage, probe the fuse terminal closest to the windshield. Observe the test lamp as you disconnect the HO2S bank 2 sensor 1 harness connector. Does the test lamp turn OFF? If yes, go to step  14. If no, go to next step.
  12. Observe the test lamp as you disconnect the HO2S bank 1 sensor 2 harness connector. Does the test lamp turn OFF? If yes, go to step  16. If no, go to next step.
  13. Repair the short to ground in the ignition 1 voltage circuit to the HO2S. After repairs, go to step  18.
  14. Replace HO2S bank 2 sensor 1. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  18.
  15. Replace HO2S bank 1 sensor 1. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  18.
  16. Replace HO2S bank 1 sensor 2. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  18.
  17. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  18. 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.
  19. 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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