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Home >> Chevrolet >> 2000 >> Impala LS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Self-Diagnostics - 3.8L >> Diagnostic Tests >> DTC P0134: HO2S CIRCUIT INSUFFICIENT ACTIVITY - BANK 1, SENSOR 1 (EXCEPT BONNEVILLE, CAMARO, FIREBIRD & LeSABRE) >> Diagnostic Procedures

Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. 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 400-500 mV range, go to next step. If voltage is not varying outside of 400-500 mV range, go to step  4.
  3. Turn ignition on. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this DTC FAILED THIS IGN, go to next step. If scan tool does not indicate that this DTC FAILED THIS IGN, see DIAGNOSTIC AIDS .
  4. Turn ignition on. Disconnect HO2S 1 harness connector. Using jumper wires, jumper HO2S 1 signal and ground circuits to ground. Monitor HO2S 1 voltage with scan tool. If voltage is less than 150 mV, go to step  8. If voltage is not less than 150 mV, go to next step.
  5. Remove jumper wire from HO2S 1 signal circuit. Using DVOM, measure voltage between HO2S 1 harness connector signal and heater ground circuits. If voltage is about 4.5 volts, go to next step. If voltage is not about 4.5 volts, go to step  7.
  6. Turn ignition off. Disconnect PCM harness connectors. Measure resistance of HO2S 1 ground circuit between HO2S 1 and PCM. If resistance is greater than 5 ohms, repair circuit as necessary. After repairs, go to step  13. If resistance is not greater than 5 ohms, go to step  9.
  7. Turn ignition off. Disconnect PCM harness connectors. Measure resistance of HO2S 1 signal and ground circuits between HO2S 1 and PCM. If either circuit resistance is greater than 5 ohms, repair circuit as necessary. After repairs, go to step  13. If resistance in both circuits 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 connections are okay, go to step  11.
  9. Check HO2S 1 ground circuit for faulty connection at PCM. Repair as necessary. After repairs, go to step  13. If connection is okay, go to step  12.
  10. Check HO2S 1 signal circuit for faulty connection at PCM. Repair as necessary. After repairs, go to step  13. If connection is okay, go to step  12.
  11. Replace HO2S 1. After repairs, go to step  13.
  12. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
  13. Using scan tool, read and record FAILURE RECORDS data, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool indicates that this DTC FAILED THIS IGN, go to step  2. If scan tool does not indicate that this DTC FAILED THIS IGN, system is okay.
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