In this guide, you will learn how to replace the oxygen sensor on a Honda Civic.
Even though oxygen sensors are not particularly maintenance items, on modern Honda vehicles they often start to fail around the 100,000 to 150,000-mile mark. Once the oxygen sensor on your Honda fails, you will notice the check engine light stays on and a decrease in fuel economy.
What you will need
- Park your Honda on level ground and allow the engine to cool down.
- When replacing the upstream oxygen sensor (Bank 1 Sensor 1 or Bank 2 Sensor 1) open the hood. If you are replacing the downstream oxygen sensor (Bank 1 Sensor 2 or Bank 2 Sensor 2) you should jack up the vehicle as these sensors are accessed from the bottom of the engine.
- Locate the oxygen sensor on your Honda engine.The upstream oxygen sensor (Bank 1 Sensor 1) is mounted on the exhaust right before the catalytic converter. Bank 1 Sensor 2 is mounted after the catalytic converter and can be accessed from under the car.
- Disconnect oxygen sensor wire harness. Use an oxygen sensor socket to remove the oxygen sensor from the catalytic converter. Turn the oxygen sensor socket counterclockwise to remove the O2 sensor.If the sensor won't come loose, spray penetrating oil near the threads and let it soak for at least 15 min.
- Remove the oxygen sensor.
- Install a new oxygen sensor. Apply a small amount of anti-seize to the threads and hand-tighten the sensor in the exhaust. Using a torque wrench tighten the new oxygen sensor to 33 ft-lb. If you don't have a torque wrench use the ratchet to tighten the O2 sensor until it is on snug tight.
- Connect the electrical connect by pressing the two ends until they click.
We replace the upstream (sensor 1) oxygen sensor which is accessed from the top of the engine. The same procedure is used to replace the downstream oxygen sensor but that sensor is easier to access from the bottom of the engine.
When your Honda oxygen sensor fails you will decrease in performance such as:
- A decrease in fuel mileage
- Difficulty starting
- Check engine light on
- Loss of power
- Excessive smoke from the tailpipe
- Failed emission (smog) test
- Hesitation, poor acceleration
- Rough idle
- Possible codes P0420, P0135, P0141, P0155, etc.
Use an OBD-II scanner to read the codes via the OBD-II port under the dashboard to confirm the oxygen sensor is defective.
Frequently Asked Questions
How often should I change my oxygen sensor?
Oxygen sensor are replaced when they fail. In many cars, oxygen sensors fail around 100,000 to 150,000-mile mark.
Can a bad o2 sensor cause a p0420 code?
Yes. P0420 code means that the catalytic converter is operating below the threshold. This code comes up when the catalytic converter is bad or the oxygen sensor is defective.
Can I use a universal oxygen sensor?
Yes you can. You may have to splice wires and will need to connect all the 4 wires correctly. The new connections tend to corrode and cause problems down the line. Make sure to insulate the wires properly.
What is Honda O2 sensor thread size?
Most common Honda oxygen sensor thread is: 18 mm x 1.5 mm
What are some symptoms that my Honda oxygen sensor is bad?
Check engine light and poor fuel econommy are the most common.
What socket size is used on the Honda oxygen sensor?
7/8" or 22 mm socket.
Honda oxygen sensor torque spec?
33 ft - lb
Is it legal to use an oxygen sensor spacer?
No. In most contries it is not legal to install an oxygen sensor spacer.
Honda oxygen sensor wire colors?
The typical color on OEM Honda O2 sensor.
Ground will be green or gray.
The signal is white or black.