was driving home tonight and the car threw a P0138. High voltage rear o2 sensor i believe. strangely enough i just had a 2.25" catback put on approx 200 miles ago. this is the only code im getting and the car seems to be running fine. is there anything i should be looking into other than the rear o2 sensor? i just find it strange it happened after my catback was put on.

 

when you put it on did you get anything such as oil, grease, dirt on the sensor because that will cause it to go bad. But i wouldn't look to far into it my same o2 sensor just went bad in my '97 3.0 cl.

 

i had it installed by a local shop who knows what they did to it. i found a OEM denso sensor for 50 dollars shipped on ebay, it should be here by the end of the week and ill see what happens, thanks for the reply. i will update this thread with my results so future users dont have the same question.

 

brakecleaner

 

**UPDATE**
i reset the ECU without doing anything else to see if this would fix the problem. its been approx 600 miles and no CEL reappearance, i even got it e-checked the other day and she passed. still have the new o2 sensor sitting in my garage in case the CEL decides to reappear. so to anyone who gets this code after a catback install try reseting the ECU by removing positive terminal for atleast 15 min. worked for me. thanks to everyone for thier input

 

**UPDATE**

CEL came back on 2 days after smog check...put the new one on and she has been good so far. for anyone in the future who gets this code i recommend just buying a denso o2 sensor from ebay. if you search for "denso 234-4601" you will get the exact OEM sensor acura put in from the factory for about $80 less than autozone wants for it. should run you about $50