Pulled a "P0133" code this morning. The definition is (O2 sensor slow response-Bank 1/Sensor 1).

Can anyone verify for me that this is the front or rear O2 sensor? I seem to remember that my S70 has two O2 sensors. One in the front and one in the rear.

Is one fo these harder to install that the other?

Thanks much!

I am now going to let my Indy mechanic do this front sensor for me. However I would like to help him by spraying the old/existing one near the threads so he might have an easier go of it. What location is best to see this front O2 sensor from? Underneath the car or from up top?

Spraying the O2 sensor with a penetrant (not WD40) will probably do nothing for your mechanic as you will drive the car to him and burn up any of the penetrant in the process. He knows it is hard to get out and has probably done several hundreds by now.

If you really want to spray, the O2 sensor can be seen from underneath.

You might want to clean off the wire connector if you can find it. Look behind the air cleaner near the top of the transmission. There are two square connectors usually covered in sand/dirt.

http://volvospeed.com/volvo_repairs_how_tos/sensor_replacement/oxygen_sensor_o2.html
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Klausc, a Volvoholic

Klaus,
After pulling the code with my reader, I cleared all codes and after two days now the P0133 code has not come back. Is this good or bad?

Banks are for V-6 and V-8, so that is to be ignored. Sensor 1 is the front and sensor 2 is the rear. So, the code is for the front O2 sensor.

Not difficult, so long as you know where the electrical plugs are. Make sure you spray the sensor with penetrating oil and let it soak in. A 7/8th wrench for O2 sensors is needed. Cheap enough at the local autoparts store.

FCP has a video.

Thanks much Klaus.
I think this one will do nicely.

http://www.amazon.com/Bosch-15097-Oxygen-Sensor-Fitment/dp/B000BZI3G2/ref=au_as_r?ie=UTF8&Make=Volvo%7C27&Model=S70%7C146&Year=1998%7C1998&carId=001&n=15684181&newCar=1&s=automotive&vehicleType=automotive

good price. Go here and scroll down a little to see the video:

http://www.fcpeuro.com/products/volvo-oxygen-sensor-front-850-c70-s70-v70-15097

Klaus, that FCP Groton video is for a turbo.
How much of a difference will it make that mine is a N/A car?

With the NA engine you can actually see the connectors on the top of the tranny without removing anything. Remember, the top of the connector pulls up to release the plug. Volvospeed.com has a pictorial for an 850:

http://volvospeed.com/volvo_repairs_how_tos/sensor_replacement/oxygen_sensor_o2.html

Klaus, last question. Do I remove this forward O2 sensor from beneath the car or from up top?

You cannot reach it from the top, even if you could, the 3/4inch tool to grab the sensor requires a LOT of torque and penetrating oil. Search for additional videos on youtube.