I have a 2002 v70 base. That is having Oxygen sensor problems (upstream sensor). It looks like someone installed a new sensor but left it unplugged. With the sensor unplugged the vehicle runs fine but throws an O2 sensor code. When I plug in the sensor, the code goes away but the car runs rough, has a lack of power and my code tool says it fails to run emissions tests. Is it the wrong sensor for the car? The Sensor has the part number
RAL01062
OS54009

 

which code is being presented? there's two types of codes which are based on the signal (ie fuel trim) or the response of the heater element (O2 sensors need to be warm to measure correctly). With the front sensor unplugged I'd expect a happy meal of codes - are you sure its the front sensor that is unplugged? The rear sensor is there to determine if the cat is functioning properly so it doesn't really alter how the engine runs.

As to the part number, it looks like there's a parts number break in 2002 so you may need to call a dealer store like Tasa or Volvo friendly web store like IPD or FCP and provide your VIN to see which sensor is correct for your car.

 

I’m getting a p0032 code with it unplugged, it is the sensor directly behind the engine, thanks!

 

well that code is saying the resistance on the heating element is too high - and since you've unplugged the circuit, you now have infinite resistance :-) Plug the sensor back in, reset the code and see what you get. Note that wonky idles usually suggest an intake air leak (torn boots, vacuum lines, leaking vacuum actuated switches etc). The O2 sensor really don't come into play until its warmed up so I'd check other things out by looking for a air leak (may take a smoke test to find it), check the coolant temp sensor resistance (2.5K at room temp, closer to 7K at 32F and about 200-300 ohms for a fully warmed up engine), check/clean the MAF. Its also possible you have an issue with the ETM (electronic throttle mechanism) - check out Xemodex.com for some diagnostic tips.