Hi all,

I have a 2003 Civic HX (not under warranty anymore) - just turned over 40,000 miles. I recently had my check engine light come on. Took my car to the Honda dealership for a diag. and they said my primary O2 sensor needed to be replaced.

So instead of paying them $400, I bought the part myself ($200 for a Bosch sensor) and replaced it. I had the code reset, but after driving 36 miles, the engine light came back on. I took my car to another mechanic for the diag. and am receiving a P1164 error (Air/Fuel Ratio (AF) Sensor (Sensor 1) Circuit Range/Performance).

It appears this error still relates to the O2 sensor, but I don't know. Can anyone shed any light on this?

BTW - after replacing my O2 sensor, my gas mileage has gone back up to it's normal level of about 40mpg.

Thanks!

Chris

 

Maybe disconnect your battery for half an hour, and start the car back up. Make sure not to hit the gas, even if the car takes a few turns to start. That way, the ECU can get a fresh start.

Just a shot in the dark.

 

Ok, will do! Don't know if that will matter...

Also, there are two O2 sensors on this model. One pre-cat (on the manifold) and one after-cat. Do you think I may need to replace the after-cat O2 sensor?

 

I would think the CEL would specify which one it was.

Stick around, though. More guru's will see your thread, and have better answers for you.

 

I just ordered the After-Cat O2 sensor since from what I am finding online (no definitive answers though), it appears I need to replace that.

Edit: Another question, what is the difference between an Air/Fuel sensor and an Oxygen sensor? You can buy both online, but they appear to be the same thing?!?!?

If any of the Guru's on here have any other ideas, please let me know!

Thanks!

 

This problem could be because of your "CAT" I had the same problem and changed the o2 and still te problem was there untill i changed the "CAT" then it went away

 

your primary O2 sensor is what takes the readings from your exhaust that tells the ecu whether it needs to richen or lean out the mixture. The secondary O2 sensors only job is to make sure the cat is functioning. Your car will run perfectly fine without a rear (after cat) O2 sensor but it will throw a light. If you didnt get the proper Bosch O2 sensor or if your soldering job is not up to par it will throw a code because it can't read the sensor properly.

 

Thanks! Actually, my question was answered this morning. You're right...the after cat O2 is not the issue. The P1164 code has to do with the mixture - which I am being told is "lean" right now. Even though the Bosch sensor was listed to work on the HX, it is common to receive this error.

I guess I should have spent the few extra bucks for the Denso! Hopefully I will get my money back!

Thanks everyone!