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Home >> Isuzu >> 2000 >> Rodeo LSE, 2.2 D >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.2L >> Diagnostic Trouble Code Identification >> DTC P0140: No Rear Ho2S Activity Detected >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic II (OBD-II) system check. See SELF-DIAGNOSTICS - INTRODUCTION article. Go to next step.
  2. Start engine and allow it to reach operating temperature. Increase engine speed to greater than 1200 RPM for 2 minutes. Using scan tool, read HO2S-2 value. If reading is switching outside of .425-.475 volt range, go to next step. If reading stays within .425-.475 volts, go to step  4.
  3. Turn engine off. Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read specified DTC. If scan tool displays DTC P0140 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0140 FAILED THIS IGN, see DIAGNOSTIC AIDS .
  4. Check for faulty connection at rear HO2S. If faulty connection is found, repair as necessary. Retest system. If connection is okay, go to next step.
  5. With ignition off, check for faulty connection at PCM. If faulty connection is found, repair as necessary. Retest system. If connection is okay, go to next step.
  6. Turn ignition off. Disconnect PCM connectors. Check resistance of rear HO2S harness connector signal circuit. If resistance is greater than 5 ohms, repair open or faulty connection as necessary. Retest system. If resistance is 5 ohms or less, go to next step.
  7. Reconnect PCM harness. Turn ignition on. Using DVOM, check voltage between each rear HO2S harness connector terminal and heater ground circuits. If reading is about 3-4 volts, go to step  9. If reading is not as specified, go to next step.
  8. Check both signal circuits for a short to ground or voltage. Repair as necessary. Retest system. If no problem was found, go to step  11.
  9. Disconnect rear HO2S harness connector. Connect jumper wires between rear HO2S harness connector high and low signal circuits and heater ground terminal. If reading is 0-.01 volt, go to next step. If reading not 0-.01 volt, go to step  11.
  10. Replace rear HO2S. Retest system.
  11. Replace and reprogram PCM using required equipment. See PROGRAMMING . Retest system.
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