Jon,
I have never replaced my 02 sensors so I can't help you on replacing them or trying to dertermine which one might be bad... sorry! As far as the codes I had the same issue when I bought my 94 850, all I did was reset them and see if they came back. Most of them didn't, a few did, I wouldn't ...

I have a subscription to AllDataDIY for my 94 850 Turbo - the description I found out there for 443 is :
4-4-3 THREE-WAY CONVERTER EFFICIENCY

The ECM continuously monitors the Three-Way Converter's (TWC ) efficiency by comparing the signal from the rear Heated Oxygen Sensor (HO2S ) with the ...

You were able to read your '94 850 diagnostic codes at AutoZone? It has an OBD port? I would again read your codes from the black diagnostic boxes under your hood and see what the Volvo specific codes are. I'm a bit surprised as I've never seen a '94 with an OBD port.

This shows you where the ...

There was a technical bulletin put out in May 1998 detailing the replacement of this metal pipe with plastic (at least that is what I think it is) vacuum line.

Connector - Crankcase Ventilation
Section
2

Group
25

No.
0001

Year
98

Month
05

Reference:
TP 2101201, Section 2 (2022, 25-26) B5204 ...

I know this question was posed over in the S80 forum, but I'm having the same problem with my 1999 S70 T5 (which I just purchased!). Here is the issue at hand:

"After first start up or after it has sat untouched for 20 minutes, the transmission just started making a sound like a quick mettalic ...

momentos wrote:thanks for your help I will look into that site...

bryang wrote:Try ozbrick.com, they have illustrated, step by step instructions....

Let me know if you can't find the right link - I was just out there a few nights ago studying their instructions as I have to do this job soon as well....

Bryan

Try ozbrick.com, they have illustrated, step by step instructions....

Hate to butt in on this post but I have a curiosity question... my Rec and A/C lights were blinking at one point but have since stopped... what might that indicate?

Thanks!

Bryan
1994 850 Turbo Wagon - stock - no mods

Matt,
Thanks for the link to the other topic on the oil leak!

Bryan

I just purchased a 1994 850 Turbo Wagon with 218,000 miles. It has a minor oil leak, and, after doing the dye thing I was able to determine that the oil is leaking from the return line and the turbo itself. Not sure what I am going to do but wait until the turbo bites it and then have it rebuilt..