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2012 Hyundai Accent Oxygen Sensor Replacement

One item that commonly breaks in modern cars is...

iFixit Library Hyundai accent Moderate 30 minutes Guide 149059

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Guide overview

Before you begin

One item that commonly breaks in modern cars is the oxygen, or O2, sensor. When they go bad, it can lead to rough idle, and if ignored, will leave motorists stranded. It is very easily diagnosed by a trouble code or check engine light. Many auto parts stores will scan cars for free, and the code provided will indicate if there is a bad O2 sensor, as well as many other possible issues. If your 2012 Hyundai Accent O2 sensor has failed, follow this guide to replace it. This fix will involve finding the sensor, unplugging it, unthreading it, and reinstalling a new sensor in its place. Reminder: Engine bays are usually very dirty, so a pair of work gloves or nitrile gloves can make clean-up easier. Thinner gloves are better for dexterity since there is a small plug to manipulate. Reminder: More lighting is never a bad thing. Headlights, a friend holding a flashlight, or magnetic lights, while not a requirement, will definitely help.

Step 1

Remove the engine cover

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Grasp the engine cover by the front edge.
Give it a firm yank upward.

Step 2

Repair step

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Grab the rear edge of the cover.
Yank it upward.

Step 3

Repair step

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The engine cover has been removed.

Step 4

Repair step

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Never work on a hot vehicle. Allow your car to cool for at least 4 hours before performing maintenance.
Never work on any automotive electronics without first disconnecting the negative (-) terminal.
Use a 10 mm wrench to loosen bolt on the battery's negative (-) cable, then slide it off the (-) negative post.

Step 5

Repair step

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Locate the sensor off the exhaust header and follow the wire up to the connector.
Some of the pieces on the top-front of the engine are sharp; be careful what you lean on.
Gently work the connector out of the bracket, then disconnect it by pressing the tab inward then pulling out.
Plastic gets brittle over time. Be gentle and go slow. If it's not coming out, take a break and come back a little later. Be patient to avoid damage.

Step 6

Repair step

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Gently pull the wire out of its bracket.
It will lift out of the bracket with minimal effort.

Step 7

Repair step

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Place the 7/8" (22 mm) socket around the O2 sensor. Use a ratchet and 6" extension to loosen and remove the sensor.
Place the socket on the sensor without the ratchet in the way. Once the socket is in place, reattach the ratchet and loosen.
The sensor is behind the exhaust, up against the firewall. Having a headlamp, or a friend who can hold a flashlight, is a big help. The red lights in these photos are cheap magnetic lights!

Step 8

Repair step

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The sensor can now be unthreaded by hand.
When installing the new O2 sensor, if you feel extreme resistance, STOP. It means it is cross threaded. It should easily thread in by hand.
Use the 7/8" (22 mm) socket to tighten the sensor firmly so it doesn't loosen from vibration.
The last picture is what the whole sensor looks like out in the open.

Step 9

Repair step

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Reconnect the plug by firmly pushing the plugs together.
Depending on the age of the plastic, you may or may not hear a click; just follow where the two plugs meet. There should be almost no gap.
Push the connector back into its bracket.
You may need to slightly wiggle the connector as you seat it into its bracket. It will be a tight fit by design.
Push the wires back into the metal brackets.

Step 10

Repair step

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Reattach the negative (-) battery cable.
Be sure to push/seat the terminal as far down as possible before tightening the 10 mm bolt.