My sister's check engine light has been on for a while. She had the code checked, and it was the O2 sensor code. I replaced both O2 sensors for her and the code cleared. Then, on her way home (25-30 minute drive) the CEL came back on. She went and had it scanned again, and it was still an O2 sensor code. She brought it back so I could put one of the old ones back in to see if maybe one of the new ones was no good. I put the old one back in the upstream location and the code cleared again. A couple of days later the CEL came back on again, guess what code, O2 sensor.

Any ideas why it keeps FUBARing O2 sensors? Or if there are any other things that may cause it to throw the O2 sensor code?

Thanks.

 

check wiring. seen this before. wouldn't doubt if you found a fried wire from being to close to the block. head. exhaust.

 

What was the actual trouble code?

If her Accord is an ULEV, then it needs an air/fuel ratio sensor (a wide band type of sensor) vs. a regular type O2 sensor for the non-ULEV. Generally, it will say ULEV on the valve cover (4 cylinder engine) unless someone swapped parts, etc. However, the trouble code is different for an A/F ratio sensor; so, that will specifically tell.

 

It is the ULEV.

I'll have to look into this.

Is it generally the upstream, downstream, or both?

 

For the 4 cylinder, IIRC only the primary needed an air/fuel ratio sensor. The secondary was an O2 sensor.

 

I guess I forgot to hit the save button after I edited my last post.

I checked Honda diagrams, and only the upstream is listed as A/F sesor, so I'll have to look into exactly which code she's getting.

Thanks.