P1171 issues

[precopster]

When my front 02 sensor failed a few weeks ago in my 2001 V70T5 it was like someone flicked a switch. The heated element circuit went open and fuel mileage plummeted, especially around town.

I had the same CEL for front O2 sensor and fitted the Bosch 17070 sensor yesterday. Today I got my first ever 7.0L/100kms (about 34mpg) on a stretch of freeway and averaged 25mpg on the whole trip. Hope it fixes yours too.

[Zorak412]

Well I replaced the rear o2 sensor and the car runs fantastic and the 1171 hasn’t shown up yet. But now I have a p0134 code saying sensor one isn’t working. Looking the code up on the forums states that it could be either sensor so I’m assuming the Bosch one I got might be bad or should I also just replace the front sensor as well?

[precopster]

I would have replaced the front sensor first as it's also responsible for P1171. However unlikely 2 sensors fail within a week of the other it IS possible.

If you read my post above on 1st December sensor 1 fixed the same code. It's the same engine and management system on the V70 as the S60.

If you read these cars with a better scanner (such as Vida-Dice) it will point to the sensor with the open heater circuit (if that happens to be the issue) Let us know how it pans out

[Zorak412]

I replaced both sensors and the car runs amazing now. It’s been running good for a few weeks and no more codes. So at least that solved my p1171 issue. I hope this helps others. Thanks everyone for the help.