Hi all...My first post...and I put it the wrong group...hope I get better.

I own a 1992 940 Sedan B230F Vin 88 8-valve with 226,000 miles. 145,000 miles are mine.
My check engine light came on a week ago and when I pull the fault codes(socket 2) it returns 2-2-1 and 2-3-1. There is no change in the performance of the car but that light on in the dash drives me batty. I have cleared the codes a few times but each time I start the car the CE light comes on within 2-3 seconds and I get both codes again. I changed the O2 sensor yesterday but I still get the same result. I did a quick check on the vacuum hoses and did not see anything obvious.

Any advice is greatly appreciated.

 

Since you swapped the O2 sensor, I'm guessing you know those are rich and lean codes on the O2. Remember, the O2 is the lone sentinel, the tail end Charlie, that gives the ecu the final report on how things are doing. By swapping in a new sensor and getting the same codes, it's a safe bet that the O2 wasn't lying! So...check for things that can cause a rich condition. Dirty air filter, faulty fuel pressure regulator, dirty AMM, engine coolant temp sensor. Also, take a good look at your intake hose from filter to the throttle body. If you haven't cleaned your throttle body lately, I guarantee it's nasty.
What I've concluded after working on LH Volvos for years is that seldom does one failed sensor upon replacement, cure the condition. It's been my experience that I could take a multi-meter and check 3-5 sensors and they all would read on the low side of acceptable. What seems to happen (and I have NO facts to back this up) is almost a synergistic effect. The combination of low performing sensors makes for a tough diagnosis. So...look for obvious stuff first.

 

Thanks for the reply. The weird thing is there is not a discernible difference in performance. Starts fine, idles fine, and accelerates fine. I guess I'll start with the air filter and work my way towards the intake...although I have replaced the air intake hose recently. I'll update as I go.

 

please let me know what you find out in your 940. I'm fighting the same issue in my 240. thanks.