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Home >> Pontiac >> 2000 >> Firebird Formula, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics - 5.7L >> Diagnostic Tests >> DTC P0141: Ho2S Circuit Insufficient Activity - Bank 1, Sensor 2 >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
    NOTE: If engine has been operating, allow engine to cool down for about 30 minutes before proceeding.
  2. Turn ignition on, with engine off. Using scan tool, select ENGINE 1 DATA LIST and monitor HO2S voltage. If voltage reading goes from bias voltage to less than 300 mV or greater than 700 mV, see DIAGNOSTIC AIDS . If voltage reading does not go from bias voltage to less than 300 mV or greater than 700 mV, go to next step.
  3. Check HO2S ignition feed fuse. If fuse is open, go to step  11. If fuse is okay, go to next step.
  4. Disconnect HO2S connector. Using a test light connected to chassis ground, probe HO2S ignition feed circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step  7.
  5. Connect test light between HO2S ignition feed and heater ground circuit at harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step  8.
  6. Check resistance between HO2S ignition feed and heater ground at HO2S pigtail connector. If resistance is 3.5-14.0 ohms, go to step  9. If resistance is not 3.5-14.0 ohms, go to step  10.
  7. Repair open in HO2S ignition feed circuit to HO2S. After repairs, go to step  12.
  8. Repair open in HO2S heater ground circuit. After repairs, go to step  12.
  9. Check for poor connection at HO2S. Repair as necessary. After repairs, go to step  12. If connection is okay, go to next step.
  10. Replace HO2S sensor. After replacing sensor, go to step  12.
  11. Repair short to ground in HO2S ignition feed circuit. Replace fuse. After repairs, go to next step.
  12. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, and then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step  2
  13. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.
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