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Home >> Chevrolet >> 1995 >> Cavalier Z24, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 2.3L (W/OBD-II) >> Diagnostic Trouble Codes >> DTC P0134 - O2S Insufficient Activity Sensor 1 >> Diagnostic Procedures

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 407-509 mV, go to next step. If scan tool does not indicate 407-509 mV, 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 407-509 mV, go to next step. If scan tool does not indicate 407-509 mV, go to DIAGNOSTIC AIDS.
  4. Turn ignition on, with engine off. Disconnect O2S 1 connector and jumper O2S 1 high signal circuit (PCM side) to ground. Using scan tool monitor O2S 1 voltage. If voltage is less than 200 mV, go to step 8). If voltage is 200 mV or greater, go to next step.
  5. Disconnect jumper wire. Using DVOM, measure voltage between ground and sensor signal circuit terminal at O2S 1 harness connector. If voltage is greater than 407 mV, go to step 6). If voltage is 600 mV or less, go to step 7).
  6. Turn ignition off. Disconnect PCM and check continuity of O2S 1 low circuit. If O2S 1 low circuit measures over 5 ohms, repair open or poor connection as necessary. If an O2S 1 low circuit problem was found and corrected, perform OBD System Check. If an O2S 1 low circuit problem was not found and corrected, go to step 9).
  7. Turn ignition off. Disconnect PCM and check continuity of O2S 1 signal circuit. If O2S 1 signal circuit measures over 5 ohms, repair open or poor connection as necessary. If an O2S 1 signal circuit problem was found and corrected, perform OBD System Check. If an O2S 1 signal circuit problem was not found and corrected, go to step 10).
  8. Check for poor O2S 1 signal or low circuit terminal connection at O2S 1 harness connector and replace terminal(s) as necessary. If any terminal(s) were replaced, perform OBD System Check. If terminal(s) was not replaced, go to step 11).
  9. Check for poor O2S 1 low circuit terminal connection at PCM and replace terminal if necessary. If any terminal(s) were replaced, perform OBD System Check. If terminal(s) was not replaced, go to step 12).
  10. Check for poor O2S 1 signal circuit terminal connection at PCM and replace terminal if necessary. If any terminal(s) were replaced, perform OBD System Check. If terminal(s) was not replaced, go to step 12).
  11. Replace O2S 1. After repairs, perform OBD System Check.
  12. Replace PCM. After repairs, perform OBD System Check.
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