Oxygen Sensor: Service and Repair

REMOVAL
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Fig.25 O2 Sensors 2.7L:

The O(2)S are located at the outlet ends of the catalytic converter.

WARNING: THE EXHAUST MANIFOLD, EXHAUST PIPES AND CATALYTIC CONVERTER BECOME VERY HOT DURING ENGINE OPERATION. ALLOW ENGINE TO COOL BEFORE REMOVING OXYGEN SENSOR.

1. Remove the negative battery cable.
2. Raise and support the vehicle.
3. Disconnect the wire connector from the O(2)S.

CAUTION: When disconnecting the sensor electrical connector, do not pull directly on wire going into sensor.

4. Remove the O(2)S. Snap-On oxygen sensor wrench (number YA 8875) may be used for removal and installation.

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The engines uses two heated oxygen sensors, one in each exhaust manifold.

CAUTION: When disconnecting the sensor electrical connector, do not pull directly on wire going into sensor.

1. Remove the negative battery cable.
2. Remove the air cleaner box for the rear O(2) sensor.
3. Disconnect the heated oxygen sensor electrical connector.
4. Use a Special tool #8439 to remove oxygen sensor.

INSTALLATION
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The O(2)S are located at the outlet ends of the catalytic converter.
1. After removing the sensor, the exhaust manifold threads must be cleaned with an 18 mm X 1.5 + 6E tap. If reusing the original sensor, coat the sensor threads with an anti-seize compound such as Loctite 771-64 or equivalent. New sensors have compound on the threads and do not require an additional coating. Tighten the sensor to 28 N.m (20 ft. lbs.) torque.
2. Install the O(2)S. Tighten to 28 N.m (20 ft. lbs.) torque.
3. Connect the O(2)S wire connector.
4. Lower the vehicle.
5. Install the negative battery cable.

Upstream 1/1, 2/1
The engines uses two heated oxygen sensors, one in each exhaust manifold.
1. After removing the sensor, the exhaust manifold threads must be cleaned with an 18 mm X 1.5 + 6E tap. If reusing the original sensor, coat the sensor threads with an anti-seize compound such as Loctite 771-64 or equivalent. New sensors have compound on the threads and do not require an additional coating.
2. Use a Special tool #8439 to install oxygen sensor. Tighten the sensor to 28 N.m (20 ft. lbs.) torque.
3. Connect the heated oxygen sensor electrical connector.
4. Install the air cleaner box.
5. Install the negative battery cable.