Speed sensor stopped working - Volvo 670

After hitting hard a bump, all of a sudden the speedometer needle went down to 0 mph, the tachometer shows max of 1350-1400 rpm and the cruise control is out. I can still somewhat accelerate and go up to 63 mph with a 25 000 lbs load. The scanguage I have shows HP output up to 350 HP at some moments The jake brakes are working.

The diagnostics show this:









I'll try to pull out the sensor during daylight and clean it with a brake cleaner and put it back to see if it helps. If not I'll go to Volvo to get the new part and replace it myself. If it is still not good that means wiring issues. The wires going to the sensor looked somewhat old and worn, so if they are the problem then I'll have a bigger issue and most likely will have to deadhead empty home. No way I am spending money on this at Volvo or any other stealership.

 

I was unable to untighten the bolt that holds the sensor with the wrenches I have at my disposal. Too old and rusty despite applying W-40 at night. I don't want to force it too much either so that it is not rounded. I'll look for other ports down there and if I see one I'll go to Volvo and get the sensor, since it is cheap and make one more effort to do it by myself hoping it is the easy "just replace the sensor" fix.
If that does not work then the wiring is the problem. I also have a feeling that that's what it is. As you can see on the photo in the first post, the sensor did not look damaged and it should not get an internal damage due to a nasty bump.

If that's wiring, I'd rather deadhead back home to resolve it there. The last time I tried to fix a wiring issue at a local Ohio shop, it snowballed into an expensive mess and I ended up towing the truck over 400 miles anyway. This time, I am away 1000 miles and still would rather deadhead than gamble time and money at an unknown local shop. Already cancelled a back haul - 45 000 lbs - too much to try to be lucky and going over Mountain Eagle Pass in TN.
The Volvo wiring is very feeble after 10 years. All these wires I see underneath are a ticking time bomb. I have to think of replacing the whole harness, if that's even an option. Or even better, get myself onto some diesel truck electrician course.

I also noticed that the Odometer is frozen and no miles are being added as I drive, so that thing depends on the speed sensor too.

 

Here's the end of story.
The very sensor replacement has not helped. It still showed the same errors after replacement.
After rerunning the wires from the sensor to the ECM everything went back to normal. As I was suspecting, the bump caused the rotten wires to break or short somewhere.
I know it is possible to program ECM in such a way that the truck has no speed or rpm limitation when it happens again.

1.5 - 2 hours of work by an experienced mechanic.
Parts and labor for this very fix made the final bill close to $200.

I am glad that I manged to limp back home without spending a penny on one of those random repair shops. Knowing life, they would've ripped me off mercilessly.
I even found a cheap but light load on my way home in Tennessee and that helped not to feel too bad about the whole trip either.