Honda Civic O2 Sensor Replacement Guide

Is your Honda Civic check engine light on, your emission reaches high levels, and black smoke comes from your exhaust? Learn how to fix the problem by replacing the Oxygen Sensor of your Honda Civic.

Even though oxygen sensors are not particularly maintenance items, they often start to fail around the 100,000 to 150,000-mile mark on modern Honda vehicles. 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

Procedure

1. Park the Honda on level ground and allow the engine to cool down.
2. Open the hood when replacing the upstream oxygen sensor (Bank 1 Sensor 1 or Bank 2 Sensor 1). 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.
3. 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.
4. Disconnect the 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 doesn’t come loose, spray penetrating oil near the threads and let it soak for at least fifteen minutes.
5. Remove the oxygen sensor. 
6. 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 snug tight.
7. Connect the electrical connect by pressing the two ends until they click.

We replace the upstream (sensor 1) oxygen sensor, accessed from the engine’s top. The same procedure is used to replace the downstream oxygen sensor, but that sensor is easier to access from the bottom of the engine.

Symptoms

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.

Check Engine Light Still On

If the check engine light is still on after you replace the Oxygen Sensor, you can use the YOUCANIC Full System Scanner to clear the stored codes. This scanner can also read and clear fault codes through every control module of the Honda vehicle.

Frequently Asked Questions

We hope you find the Honda Civic O2 Sensor Replacement Guide helpful. Check these troubleshooting and repair guides for more help on your Honda Civic.