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Home >> Oldsmobile >> 1998 >> Regency >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Systems Tests W/Codes >> Diagnostic Trouble Codes >> DTC P0134 - Ho2S 1 Circuit Insufficient Activity >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. After performing OBD system check, go to next step.
  2. Start engine and allow it to reach operating temperature. Place gear selector in Park or Neutral, and apply parking brake. Increase engine speed to greater than 1200 RPM for 2 minutes. Using scan tool, read HO2S 1 voltage. If voltage is varying outside of 0.4-0.5 volt range, go to next step. If voltage is not varying out of 0.4-0.5 volt range, go to step 4),
  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. Connect a jumper wire between HO2S 1 harness connector signal and ground circuits, and chassis ground. If voltage is less than 0.15 volt, go to step 8). If voltage is not less than 0.15 volt, go to next step.
  5. Remove jumper wire. Using DVOM, check voltage between HO2S 1 harness connector signal and heater ground circuits. If voltage is about 0.45 volt, go to next step. If voltage is not about 0.45 volt, go to step 7).
  6. 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 and go to step 13). If resistance is not greater than 5 ohms, go to step 9).
  7. Turn ignition off. Disconnect PCM connectors. Check resistance of HO2S 1 harness connector signal circuit. If resistance is greater than 5 ohms, repair open or faulty connection as necessary. After repairs, go to step 13). If resistance is not greater than 5 ohms, go to step 10).
  8. Check for faulty connection at HO2S 1. Repair as necessary. After repairs, go to step 13). If no faulty connection is found, go to step 11).
  9. Check for faulty connection at PCM. Repair as necessary. After repairs, go to step 13). If no faulty connection is found, go to step 12).
  10. Check for faulty connection at PCM. Repair as necessary. After repairs, go to step 13). If no faulty connection is found, go to step 12).
  11. Replace HO2S 1. After replacing sensor, go to step 13).
  12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  13. Using scan tool, read and record FAIL RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, select SPECIFIC DTC INFO for DTC P0134. If scan tool displays DTC P0134 FAILED THIS IGN, return to step 2). If scan tool does not display DTC P0134 FAILED THIS IGN, repair is complete.
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