Introduction: Tutorial: Replace 2004 Honda Civic EX Air Fuel Sensor / O2 Sensor

Learn how to change the air fuel sensor in a 2004 Honda Civic EX. This tutorial is only for the 04-05 Civic EX/Si models. All other 7th gen Civic models are similar, but not exactly the same. If you live in a state where they do smog checks, this will affect you. I didn't pass smog the first time because of this code, but once I changed out the sensor, the car passed with flying colors!

Here's the code I was throwing below:

P0134 Honda - Air/Fuel Ratio Sensor Bank 1, Sensor 1 Heater System Malfunction

Below is the code for all other Civic models, same thing, just says O2 sensor instead of Air Fuel sensor.

P0134 (O2 sensor circuit no activity detected (bank1, sensor1)

Genuine Honda part


Denso model I bought (OEM part)