How to Replace a Buick Oxygen Sensor

While the oxygen sensor is not a normal part of the routine maintenance schedule, it should be because the sensor is one of those parts that will most likely need to be replaced sometime during your ownership. You may even need to replace it more than once as it is subject to extreme temperatures and wear. You may not know when to replace it, but you may notice some signs that your vehicle is not running right. Additionally, you may see the Check Engine Light is illuminated.

Buick O2 sensor

The Purpose of the O2 Sensor

The oxygen sensor measures the oxygen in the exhaust gas. It measures and compares the amount of oxygen within the exhaust and the amount of oxygen in the air. Then it sends that information to the car’s computer to make adjustments to the fuel to air ratio. If there is a problem with the sensor, the computer on your Buick can be receiving the wrong information, which can make the engine run too rich or too lean.

Here are some of the symptoms of an oxygen sensor problem:

Poor Fuel Efficiency

Due to the incorrect readings, the mixture between the fuel and air can be miscalculated. This may make the vehicle use more fuel than necessary, thus reducing your fuel efficiency.


If your oxygen sensor is bad, it can advance or slow down the engine ignition timing if they are aligned. This will make your engine ping. That means that the gases are being ignited at the incorrect time.

Engine Idle

A bad oxygen sensor will cause the idle to be rough. The oxygen sensor is responsible for timing, fuel mixture and combustion. When the sensor is bad, all of these things can contribute to a rough idle.


Like the rough idle, the oxygen sensor may be suppressing the air to fuel ratio, which can cause a bad mixture in the engine. This will cause the engine to misfire.


  • 7/8-inch wrench
  • Anti-seize paste
  • Crimp connectors
  • WD-40
  • Oxygen sensor

You will find the oxygen sensor on the precatalytic converter by the right front wheel on your Buick.


  1. Take off the large air intake pipe on the air box and rear turbo if you have one. Disconnect the smaller pipes from the blowoff and air box. You should be able to find the oxygen sensor. Liberally apply WD-40 in order to loosen it up.
  2. Take your wrench and remove the sensor. You will see the stock sensor wire by the engine lift loop. You need to splice that wire. Connect the wires to the new sensor by using your crimp connectors.
  3. Put anti-seize paste on the new sensor threads. Do not get it on the sensor. This makes it easy for you to remove in the future.
  4. Use your hand to screw the new sensor into place.
  5. Tighten it up with the wrench and place the connector wires in the wire holder.
  6. Reconnect the pipes and put all the parts back on.

When you fire up your Buick, you should notice a marked improvement in engine idle and fuel mileage. If you have problems with locating or replacing the sensor, then contact your local Buick dealership for assistance.