No brake pedal position sensor on the servo? 1995 850 T-5

[kalf]

I have a 1995 (November so might be MY1996 I'd guess) 850 T-5R with an automatic transmission that is having the issue of ABS + TRAC OFF lights turning on when I accelerate fast, turn off after restarting the car and turn on again when accelerating. Diagnostics is giving me ABS code 1-4-1 "brake pedal sensor". A quick search lead me to numerous articles and posts saying you need to check/repair/replace the brake pedal position sensor on the servo.

At first it made me feel stupid that I couldn't find one on my brake servo, after some more research I found some posts which still had pictures in it that confirmed there was no sensor or hole for it on my brake servo. I've also found 1 post where someone asking about not having a brake position sensor on their 1996 850's brake servo but that never really got answered.

Does anyone here have the knowledge to solve this mystery? Is the sensor located somewhere else or is it just a different sensor? The only brake related sensors I seem to find are the brake pressure sensor on the master cylinder, the brake light switch and the brake switch for the cruise control.

The ABS unit on this car looks like it's never been opened (or someone did an extremely neat job opening it and sealing it back up), so removing that to check the solder joints is next on my list.

[hausmeister]

We have pretty similar cars - I replaced the complete ABS/Tracs unit on mine with a regular one since it was leaking. I don't remember that there are any sensors mounted to the unit, so it would have to be internal I guess? Don't know if they have one.

I think I saw the thread that you mean (https://volvoforums.com/forum/volvo-850 ... 1-a-19044/ ?), but this sounds like it could be the sensor that is on the brake booster? That might make sense if you have some vacuum issue under boost or something...

I still have the old tracs unit, but I don't even know what I would be looking at. If you want I can take some more pictures or something.
that is the thread regarding the tracs delete viewtopic.php?t=97867
https://i.postimg.cc/YqnvTnrH/IMG-20211002-133351.jpg this is the sensor I mean (above blue vacuum hose)