I have a 97 850R turbo that i've had a couple months and am finally getting around to working on. The check engine light has been on since i got it and the idle is not quite as smooth as it should be. I finally got a scanner (obd2) and pulled the codes today.
P0172 system too rich (bank1)
P0133 O2 circuit slow reponse (bank 1 sensor 1)
P0440 Evap Emission system

I am new to working on anything this new (!) so i was hoping for a little guidance as to an order of tests to perform and narrow it down. Is it possible that the evap valve is bad and that this is causing all of the other readings? Does the O2 circiut code mean that one of the sensors is bad , or just that it is getting a bad reading? I have a very basic understanding of how these computer systems work but i've never had to work on them with only a code reader, usually had a real diagnostic tool. Any help would be greatly appreciated. Oh yeah, the scanner has freeze frame data for the first code only, i can post it if it would be helpful. I'm not really sure what it means. Thanks. Aaron

 

First thing I would do is check good for a Vacuum leak.

The O2 might be toast as well the slow response usually means it is bad.

The evap valve might be causing the vacuum leak as well.

 

which side of the evap valve do you pull the vacuum on? manifold side? what does "bank 1 sensor 1" mean and how does one go about testing an O2 sensor?

 

You pull vacuum from the intake.

If you can read live data with the scanner then look at the O2 sensor voltage it should be sweeping. If it is steady then it is bad.

 

by intake you mean manifold side or from the canister? the scanner wont read live data so i'm assuming i have to crawl under there and get a voltage reading from the oxygen sensor with a multimeter. What are the values supposed to be?

 

Yes the Intake manifold. One side of the valve goes to the motor the other side goes to the canister.

It should sweep between 1/2 volt to 1 I believe. I use a scanner to read it. The volt meter is a little different.

The plug for the O2 sensor it mounted to the transmission backside.

 

I thought this vehicle had two O2 sensors. What does the bank one sensor 1 mean?

 

There is only one bank on the 850. Sensor one is front O2 sensor.

 

thanks a lot for the help! i'll get in there tomorrow and see what i can figure out.

 

Sounds like a plan.

 

>I am new to working on anything this new (!)
Welcome to the club!

I also believe your 850 deserves a good tune-up in addition to Tech’s help. See my 2nd reply at: https://volvoforums.com/m_48928/tm.htm


JPN