How To Replace A Mazda Oxygen Sensor

An oxygen (O2) sensor is an essential emissions-related component that determines how efficient and clean the engine is running. A malfunctioning oxygen sensor can cause several problems, including poor drivability, reduced fuel economy, or excessive tailpipe emissions. In another blog post, we discussed how to diagnose a failing oxygen sensor. If you've done enough trouble shooting to determine your O2 sensor is bad, we're here to show you how to replace it. If you're still unsure where you want to buy your O2 sensor, check out our post about all the reasons why OEM Mazda O2 Sensors Are Better Than Aftermarket.

Tools And Supplies You'll Need

DIY tools

Replacing your own oxygen sensor can save you a lot of money on expensive repair shop labor. You may need to buy a few inexpensive tools, but it's a good investment for future DIY auto repairs. An OBD II code reader is an essential tool for many auto repairs. The best option is a BlueTooth-enabled scanner you can connect to your smartphone. These can be purchased for around $30 and will always come in handy. Here's what you'll need to replace your O2 sensor:

  • Replacement oxygen sensor
  • Oxygen sensor socket (this socket accommodates the wiring coming from the sensor)
  • OBD II code reader
  • Penetrating oil
  • Small wire brush
  • Anti-seize compound
  • Jack and jack stands or ramps
  • Safety glasses
  • Work gloves

Replacing The Oxygen Sensor

OEM mazda oxygen sensor

Remember to never replace an oxygen sensor when the engine is hot. Wait a few hours for the engine and exhaust system to cool, and then follow the steps below.

  1. Determine the exact location of your O2 sensor - your owners manual should have the information.
  2. If necessary, position the vehicle on ramps or raise it with a jack and support it with jack stands for easier access. NOTE: Make sure the emergency brake is applied and the wheels are chocked to prevent unwanted vehicle movement.
  3. The oxygen sensor threads could be seized from regular heat cycles or corrosion. Before attempting removal, spray around the threads with penetrating oil. Let it saturate the threads for about 10-15 minutes.
  4. Disconnect the oxygen sensor electrical connector.
  5. Position the socket around the sensor and gently try to loosen it with a long ratchet. If the sensor is not turning freely, you may need to start the engine and heat up the exhaust for easier removal. (Be sure you do NOT touch the hot exhaust - wear gloves and use caution to avoid injury.)
  6. When the old oxygen sensor is removed, clean the threads on the exhaust flange with a small wire brush to remove any rust or sediments.
  7. Before installing the new O2 sensor, apply an anti-seize compound to the threads for easier removal in the future. When installing the new sensor, be aure you do NOT touch the tip of the new oxygen sensor. This can contaminate the sensor element and shorten its life.
  8. Carefully install the new oxygen sensor and tighten it firmly.
  9. Reconnect the oxygen sensor electrical connector.
  10. Use a code scanner to clear any Diagnostic Trouble Codes (DTCs) from the engine computer.
  11. Test drive your car to verify the repair has corrected the problem.

The Best Quality Parts At The Best Prices

Performing your own car repairs gives you the experience to tackle more repairs yourself down the road. Whenever you have questions about high-quality parts for your Mazda, we're here to help. When you buy your replacement O2 sensors from REALMazdaParts.com you can rest assured that:

  • We have the right OEM oxygen sensors for your specific Mazda vehicle.
  • All our OEM parts are backed by Mazda's manufacturer warranty.
  • If you have any questions, we're always here to help. Please contact us!