Hello all.

I'm hoping someone can offer some assistance. I've got a 2011 XC70 t6 with 170k miles. Literally just got it yesterday shipped from Connecticut to California.

Problem is, it failed emissions with a permanent dct p0420.

I have an iCarsoft i906 and was looking through all the car data and ran across the o2 sensors running an odd voltage. From what I've read, the front (upstream) sensor should be fluctuating from 0.1v to 0.9v, however it's sitting at a solid 1.0v and not fluctuating.

My question, does anyone know if that is a bad reading for the front o2 sensor?

Thank you.

 

the P0420 is telling you the rear (downstream) O2 sensor's reading is out of the predicted range. That can means one of three things 1) the front sensor can no longer fully compensate for the fuel trim 2) the cat is not able to fully catalize the remaining fuel or 3) one of the O2 sensors is not working correctly. Sounds like your front O2 may be working too hard - which can be signs of an intake air leak or an exhaust leak throwing off the sensor. that's where I'd start looking before digging into the sensors and cat(s).