LEMON Manuals: Even more car manuals for everyone
Home >> Isuzu >> 2000 >> Rodeo LSE, 2.2 D >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 2.2L >> Diagnostic Trouble Code Identification >> DTC P0135: Front Ho2S Heater Circuit >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic II (OBD-II) system check. See SELF-DIAGNOSTICS - INTRODUCTION article. Go to next step.
    NOTE: If engine has been operating, allow engine to cool for about 30 minutes before proceeding with diagnostic testing.
  2. Turn ignition on, engine off. Using scan tool, read HO2S-1 value. If readings are fluctuating and go from greater than .65 volt to less than .25 volt, see DIAGNOSTIC AIDS . If reading is not as specified, go to next step.
  3. Inspect HO2S SENSOR (20-amp) fuse in underhood fuse/relay block. If fuse is blown, go to step  15. If fuse is okay, go to next step.
  4. Turn ignition off. Raise and support vehicle. Disconnect front HO2S harness connector. Connect a test light between chassis ground and PCM-side of front HO2S harness connector Red/Blue wire (ignition feed). If test light illuminates, go to next step. If test light does not illuminate, go to step  7.
  5. Connect test light between PCM-side of front HO2S harness connector Red/Blue wire (ignition feed) and Black wire (heater ground). If test light illuminates, go to next step. If test light does not illuminate, go to step  8.
  6. Allow front HO2S to cool for at least 10 minutes. Using DVOM, check resistance between ignition feed (Red/Blue wire) and heater ground circuit (Black wire) at front HO2S. If resistance is 3-6 ohms, go to step  9. If resistance is not as specified, go to step  10.
  7. Repair open circuit in Red/Blue wire between HO2S SENSOR (20-amp) fuse in underhood fuse/relay block and front HO2S harness connector. Retest system.
  8. Repair open front HO2S heater ground circuit (Black wire). Retest system.
  9. Check for faulty connection at front HO2S harness connector. If faulty connection is found, repair as necessary. Retest system. If connection is okay, go to next step.
  10. Check for faulty connection at front HO2S ground and signal circuit harness connector. If faulty connection is found, repair as necessary. Retest system. If connection is okay, go to next step.
  11. Turn ignition off. Disconnect PCM connectors. Check resistance of Red and White wires between PCM and front HO2S harness connector. If resistance on either circuit 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.
  12. Check Red wire for faulty connection at PCM White 32-pin harness connector terminal C15. If faulty connection is found, repair as necessary. Retest system. If connection is okay, go to next step.
  13. Check White wire for faulty connection at PCM White 32-pin harness connector terminal C14. If faulty connection is found, repair as necessary. Retest system. If connection is okay, go to next step.
  14. Replace front HO2S. Retest system.
  15. Locate and repair shorted condition in front HO2S ignition feed circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. Replace fuse. Retest system.
scientia non olet · About LEMON Manuals