How to Replace the O2 Sensor on a 2003 Suburban

by Dan Ferrell
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The oxygen (O2) sensors have a direct impact on your 2003 Chevrolet Suburban’s fuel efficiency. They provide critical data for the computer to control the air/fuel mixture going into each cylinder. Thus, a worn-out oxygen sensor not only fails to properly communicate with the computer but may increase fuel consumption dramatically. Stop wasting money and get the engine back to proper operation by replacing a failed sensor or sensors in your Chevy Suburban. This procedure applies to 4.8L, 5.3L and 6.0L engine models.

Removing the Oxygen Sensor

Step 1

Drive your Suburban for about 20 minutes to bring the engine to operating temperature. This will ease the oxygen sensor’s threads from the exhaust pipes and make it easier to remove.

Step 2

Release the parking brake, shift the transmission to neutral and detach the ground battery cable using a wrench.

Step 3

Lift the front of your Suburban on a pair of portable ramps and jack up the rear on jack stands, using a floor jack.

Step 4

Locate the oxygen sensor you want to replace. You will find the two upstream sensors on the front exhaust pipes, located between the exhaust manifold and the catalytic converter. Usually they are mounted on the pipes by the side of the transmission. You will find the two downstream sensors on the exhaust pipes that go from the rear of the catalytic converters to the rear of the vehicle. Usually they are mounted close to the converters.

Step 5

Follow the electrical wire attached to the back of the oxygen sensor to find the electrical connector. Detach the small plastic stick (connector position assurance or CPA) securing the oxygen sensor connector to the plug and unplug the sensor connector.

Unscrew the oxygen sensor from the exhaust pipe with a ratchet, ratchet extension and an oxygen sensor socket.

Installing the New Oxygen Sensor

Step 1

Apply anti-seize compound to the threads of the new sensor, if the new unit does not come with the compound already applied. This will help remove the sensor next time you need to replace it.

Step 2

Hand-start the new sensor into the exhaust pipe. Tighten the sensor to 30 ft-lbs. (41 Nm), using a torque wrench, ratchet extension and oxygen sensor socket.

Step 3

Plug in the sensor electrical connector and secure the connection with the CPA.

Step 4

Lower the rear of your Suburban off the jack stands with the floor jack and move the vehicle off the ramps.

Attach the ground battery cable with the wrench.

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