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Home › Isuzu › 1997 › Rodeo LS, 2.6 E › Repair and Diagnosis › Engine Performance › System › Engine Controls - Tests W/Codes - 2.6L › Circuit Testing › DTC P0134 - Ho2S Insufficient Activity Sensor 1 › Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. See BASIC TESTING article. Go to next step.
  2. Start engine and allow it to reach normal operating temperature. Apply parking brake and increase engine speed to greater than 1200 RPM for 3 minutes. Using scan tool, read HO2S 1 voltage. If voltage is 0.4-0.5 volt, go to step 4). If voltage is not 0.4-0.5 volt, go to next step.
  3. Turn engine off. Turn ignition on, engine off. Using scan tool, read and record FAIL RECORDS data. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0134 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0134 FAILED THIS IGN, see DIAGNOSTIC AIDS  .
  4. Inspect sensor harness for damage, repair as necessary. Retest system. If harness is okay, go to next step.
  5. Check for faulty connection at HO2S 1 signal and ground circuit. If faulty connection is found, repair as necessary. Retest system. If connection is okay, go to next step.
  6. Check for faulty connection at PCM signal and ground circuit. If faulty connection is found, repair as necessary. Retest system. If connection is okay, go to next step.
  7. Turn ignition off. Disconnect PCM connectors. Check resistance of HO2S 1 harness connector signal circuit. If resistance is greater than .5 ohm, repair open or faulty connection as necessary. Retest system. If resistance is .5 ohm or less, go to next step.
  8. Turn ignition off. Disconnect PCM connectors. Check resistance of HO2S 1 harness connector ground 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.
  9. Turn ignition on, engine off. Disconnect HO2S harness connector, connect a jumper wire from HO2S 1 harness connector signal and ground circuits to chassis ground. Using a scan tool, read voltage. If voltage is about 0.10 volt, go to next step. If voltage is not about 0.10 volt, go to step 11).
  10. Replace HO2S 1, Retest system.
  11. Replace PCM. Program replacement PCM using required equipment. Retest system.
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