GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Cobalt 🢒 Engine 🢒 Engine Controls and Fuel - 2.4L 🢒 Heated Oxygen Sensor Replacement - Sensor 1

Tools Required

J 39194-C Oxygen Sensor Wrench

Removal Procedure

Notice: The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor.

Notice: The use of excessive force may damage the threads in the exhaust manifold/pipe.

Important: 

   • The in-line connector and louvered end must be kept clear of grease, dirt or other contaminants. Avoid using cleaning solvents of any type. DO NOT drop or roughly handle the heated oxygen sensor (HO2S).
   • The HO2S may be difficult to remove when the engine temperature is less than 48°C (120°F).


    Object Number: 1631387 Size: SH
  1. Remove the exhaust manifold heat shield studs (2).
  2. Remove the exhaust manifold heat shield (1).

    3. Object Number: 1647986 Size: SH
  3. If equipped with regular production option (RPO) MN5, perform the following steps, remove the connector position assurance (CPA) retainer.
  4. Disconnect the engine harness electrical connector (2) from the HO2S.
  5. Remove the HO2S connector clip from the thermostat housing.

    6. Object Number: 1648166 Size: SH
  6. If equipped with RPO M86, perform the following steps, remove the CPA retainer (2).
  7. Disconnect the engine harness electrical connector (1) from the HO2S.
  8. Remove the HO2S connector clip from the thermostat housing.

    9. Object Number: 1631780 Size: SH
  9. Using the J 39194-C , remove the HO2S.

Installation Procedure

Important: A special anti-seize compound is used on the heated oxygen sensor threads. The compound consists of a liquid graphite and glass beads. The graphite will burn away, but the glass beads will remain, making the sensor easier to remove. New or service replacement sensors will have the compound applied to the threads. If a sensor is removed and is to be reinstalled, the threads must have an anti-seize compound applied prior to installation.


    Object Number: 1631780 Size: SH
  1. If necessary, coat the threads of the HO2S with anti-seize compound GM P/N 12377953 or Saturn P/N 21485279 or equivalent.

    2. Notice: Refer to Fastener Notice in the Preface section.

  2. Using the J 39194-C , install the HO2S.

    3. Tighten
    Tighten the sensor to 42 N·m (31 lb ft).


    Object Number: 1648166 Size: SH
  3. If equipped with RPO M86, perform the following steps, connect the engine harness electrical connector (1) to the HO2S.
  4. Install the CPA retainer (2).
  5. Install the HO2S connector clip to the thermostat housing.

    6. Object Number: 1647986 Size: SH
  6. If equipped with RPO MN5, perform the following steps, connect the engine harness electrical connector (2) to the HO2S.
  7. Install the CPA retainer.
  8. Install the HO2S connector clip to the thermostat housing.

    9. Object Number: 1631387 Size: SH
  9. Install the exhaust manifold heat shield (1).
  10. Install the exhaust manifold heat shield studs (2).

    11. Tighten
    Tighten the studs to 22 N·m (16 lb ft).