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Home >> Buick >> 1996 >> Century Custom >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes - 2.2L >> Diagnostic Trouble Codes >> DTC P0134 - O2S Insufficient Activity Sensor 1 >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
  2. Ensure engine is at normal operating temperature. Start engine. Increase engine speed to 1200 RPM for 2 minutes. If scan tool indicates closed loop, go to next step. If scan tool does not indicate closed loop, go to step 4).
  3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If scan tool indicates closed loop, go to next step. If scan tool does not indicate closed loop, go to step 12).
  4. Turn ignition on, with engine off. Disconnect O2S 1 connector. Connect a jumper wire between ground and sensor signal circuit terminal at O2S 1 harness connector. If voltage is less than 200 mV, go to next step. If voltage is 200 mV or greater, go to step 6).
  5. Turn ignition off. Inspect O2S 1 harness connector for faulty terminals or poor connection. Repair as necessary. After repair is completed, go to step 12). If connector is okay, go to step 9).
  6. Turn ignition on, with engine off. Disconnect jumper wire. Using DVOM, measure voltage between ground and sensor signal circuit terminal at O2S 1 harness connector. If voltage is greater than 600 mV, go to step 10). If voltage is 600 mV or less, go to next step.
  7. If voltage reading in step 6) is less than 300 mV, go to step 11). If voltage reading is greater than 300 mV, go to next step.
  8. Replace PCM. Program PCM using required equipment. After repairs, go to next step.
  9. Replace oxygen sensor. After repair is completed, go to step 12).
  10. Check O2S 1 ground circuit for open or poor connection at PCM. Repair as necessary. After repair is completed, go to step 12). If circuit is okay, go to step 8).
  11. Check O2S 1 signal circuit for open or poor connection at PCM. Repair as necessary. After repair is completed, go to next step. If circuit is okay, go to step 8).
  12. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0134. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2).
  13. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.
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