1995 850 Wagon.
Hi Guys, I wanted to post this in case it helps anyone.
Since about 5 years ago the car would intermittently throw CEL with port A1 showing code 232. There were no driveability issues so I ignored the problem since the CEL would go off and not show up for weeks at a time.

About 3 years ago, I had placed the battery on a charger and when reconnected, the car would not shift out of 1st gear until revved high. At that point the shift arrow would also flash. If I depressed the winter mode switch, the car would shift out of 1st. I'd then depress winter mode to resume normal driving. This would only be needed once per day after a cold start. The CEL would also come on with code 232 on A1.

The car was taken to a local indie who replaced PNP and trans. speed sensor. The problem persisted. Next I took the car to a trans. specialist who kept the car for 2 weeks, dismantling the torque converter, etc. After a $2,500 bill, was told the ABS module needs replacing. We took the car back and noticed the ABS light coming on in addition to the other lights. What a mess!

The car was then driven regularly since all issues kept occurring intermittently.

About 6 months ago, a new problem surfaced in addition to the CEL, ABS, shift arrow and lock up in 1st gear. On cold starts, all instrument gauges would randomly stop working and the car would downshift to 1st gear. Once the engine was warm, there would be no driveability issues.

Checking codes, I now got code 141 and 142 for brake pedal sensor. Replacing the brake pedal sensor fixed that issue but the CEL, shifting issues and instrument gauges still acted up.

Next I replaced the ABS module with a used one. This eliminated the ABS light but the other problems persisted and the car became unusable for the most part. A new problem then started: The service light would constantly flash and the low fuel light would flash when the ignition key was moved to ACC.

I next took a chance and replaced the instrument cluster with a used old one. All issues are now resolved. The car runs like new.

So, it seems the older 850s (pre 1996) can throw code 232/P0500 with shifting issues because the instrument cluster fails. I'm thinking may be a bad solder joint somewhere.