How to Replace the Oxygen Sensor in a Hyundai Elantra

by Jody L. Campbell

The Hyundai Elantra has been around since 1991, but wasn't made available in North America or Europe until 1993. Featuring different four-cylinder engines throughout its generational redesigns, replacing the oxygen sensors has remained a fairly standardized repair for the imported car. The upstream sensor is in the manifold or front head pipe and the downstream sensor is near the catalytic converter. The same tools can be used to replace either one, but the sensors are slightly different part numbers and are not interchangeable.

Step 1

Start the Hyundai Elantra for five minutes or so to warm up the exhaust. Drive it up onto the car ramps, apply the parking brake, shut the car off and then block one of the rear wheels with a wheel block. If you're replacing the front oxygen sensor, release the hood latch before getting out of the Elantra and then open the hood after setting the wheel block.

Step 2

Crawl under the Elantra with the tools and replacement sensor(s). Locate the sensor in question; front upstream sensor near the manifold and downstream sensor near the catalytic converter.

Step 3

Apply a generous amount of penetrating oil to the area where the threads of the sensor connect to the pipe or manifold. Allow five to 10 minutes for it to soak in. Apply a second coat if necessary.

Step 4

Disconnect the oxygen sensor wire from the wire harness plug connection. A small straightedge screwdriver may help release the press-in tabs of the plug, but be careful since its made of plastic.

Step 5

Use the swivel-head ratchet and oxygen sensor socket to remove the front sensor or a 22 mm wrench for the downstream sensor. Be sure the wire of the sensor is placed in the slot of the oxygen sensor socket. For the 22 mm box-end wrench, feed the wire through the wrench first and then place the box-end side onto the hexagonal shaped sensor. Apply steady pressure on the ratchet or wrench in the counterclockwise position to unscrew it from the exhaust system.

Step 6

Screw the new sensor into the oxygen sensor port. Most all Bosch direct fit sensors have a light coating of anti-seize compound on the thread to make removal of the sensor for the next replacement easier. Do not to allow the anti-seize compound to contaminate the thimble-shaped tip of the sensor.

Step 7

Tighten the sensor until it feels snug. Do not over-tighten as the threads of the sensor are delicate and you can easily strip them. Plug the sensor wire back into the wire harness.

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