Hi , My wife and my self both have 1999 V70's with approximatly 145k on each. They both recently failed emissions during inspection. I have replaced both O2 sensors and reset the MIL light with my code reader. After about 20 minutes the MIL comes back on and I read a P0136 code (Bank 1 Sensor 2 ). I've heard that there is a special drive cycle required after sensors are replaced.
Any help would be appreciated.

Thank You

Eric

 

ericr,
Try this.

https://volvoforums.com/m_46624/tm.htm
good luck
v70 2.4t

 

The drive cycle is not very likely going to fix your problem, A drive cycle just simulates a normal driving routine compressed into a shorter time period,
Two other possiblilties is an exhaust leak or a bad catalytic converter.