My 99 V70 has 95,000 miles, at 88,000 miles the front o2 was replaced after a check engine light came on.
now at 95,000 miles the cel came on.
PO171B Bank 1 system to lean.
P1032 See service manual
PO136 o2 sensor B1 S2 MALF

I reset the codes! The PO136 was the only code that kept returning in just minutes. This looked pretty simple ( replace the involved component) Purchased the new expensive Volvo rear o2 sensor. reset code, road test, after any drive th elight always returns when the V70 coasts. as long as th ecodes were reset and throttle was applied th elight will remain out for as long as you are on the throttle. any ideas? I am thinking I will need a proper Volvo PC scan tool to pinpoint this? any other ideas? I have the genysis next generation scan tool from OTC the best cars are good at keeping there secrets unless we have the Volvo tools!
Thanks in advance.