2004 Chevrolet Impala LSFACTORY OEM SERVICE PROCEDURE

Removal Procedure

    NOTE: The oxygen sensor may be difficult to remove when the engine temperature is below 48°C (120°F). Excessive force may damage threads in the exhaust manifold or the exhaust pipe.
  1. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical 3.8L.
  2. Remove the heated oxygen sensor (HO2S) electrical CPA retainer.
  3. Disconnect the HO2S wiring harness connector (3) from the HO2S electrical connector (4).
  4. Remove the HO2S electrical connector (4) from the fuel injector sight shield bracket (1).
    5. IMPORTANT: Remove the oxygen sensor with the engine temperature above 48°C (120°F). Otherwise the oxygen sensors may be difficult to remove.
  5. Use the J 39194  to remove the HO2S (2). See Special Tools and Equipment .
    6. Fig 1: Removing HO2S (Position 1)
    GM371512Courtesy of GENERAL MOTORS CORP.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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