1999 Accord 2.3l Calif ULEV with 270k miles AT
CEL code P1167 came on last week. Engine was running smoothly with plenty of power. I purchased a Denso 234-9025 H2OS from the internet and replaced the sensor today. The engine runs poorly with a noticeable miss that I can see in the rapid oscillation of the tach throwing a different code, P1149. This sensor is on top next to the exhaust manifold. Unplugging the sensor immediately smooths out the engine and I have plenty of power on acceleration. What's wrong??

 

P1149 is for the front A/F sensor "range & performance problem".

The ULEV takes a completely different sensor for the front A/F sensor. I can't look up that Denso part number right now, but that's my first thought is you might have the sensor for the non-ULEV engine.

 

Redbull-1 says Denso 234-9025 is the correct sensor for the ULEV engine?? I disconnected the battery for several minutes to let the computer relearn the settings but that did not work?

 

The old sensor was marked " DU DENSO 192400-1000 02U18" and has been in the car at least 7 years. About 3 years ago it threw a oxygen sensor code but, but after erasing the code, the CEL did not return. It has repeated this scenario approximately yearly, until this time that is.... after erasing the code the CEL comes back on within a few seconds of starting the engine.