Replacing ABS Modual??

Put a new one on there. You might gain a benefit from it's factory warrantry too.

As a rule you don't put used electronics onto a 18 wheeler. Not with something that important.

And don't worry, if your computer throws a code or three, then something is not right.

 

Generally the abs controllers are not OEM specific, so you should be able to change it without any issue as far as the trucks electronic codes are concerned.
I have seen aftermarket brand name controllers for not much more then that used price at truck part stores .

 

The ABS module won't add miles to the ODO, that's the CECU (cab controller). If it is water causing the issue at controllers on the inside of the cab you're going to wanna get the cab waterproofed because if you don't you'll be paying that 2000 again in a year. It's not uncommon for cabs to take in water. I see it about 1 in ever 50 trucks

 

It's very possible for the ABS to add miles, I just had that happen on a Pete. But, there was an ABS fault and a fault in the CECU. The speedo was also showing speed sitting still. The CECU gets is a speed input from the engine (from the VSS). It also gets wheel speed from the ABS sensors as a back up signal so if your VSS fails, the speedo still works and the engine gets a speed signal. When something fails, I guess the CECU decides which one make more sense and uses it, but in my case it chose wrong.

On my issue a windshield leak ran down the ABS harness and flooded the ABS ECU. I did have an ABS warning light for open/short to both rear sensors. The speedometer was showing about 35 MPH sitting still and when I hooked up, ACom also said 35 MPH on both drive wheels. I unplugged the sensors at the wheels and it dropped to about 20 MPH. I unplugged the ABS ECU and the speedo went to zero.

My ECU was $650.00 (part # K058637), Bendix EC-60. I also replaced the under dash ABS harness that was about $200.

 

That's a new one on me. I've never seen the wheel speed sensors work the speedometer only the VSS. The reason I can swear to that is during stationary regens sometimes the VSS will pick up just enough stray voltage from the chassis harness that it will actually log 1 MPH which then kicks out the regen and it's annoying when you're trying to work on a second unit and it keeps cutting out of regen. So to temporarily make it stop I disconnect the VSS and regen will complete without kicking out. The I go to park the vehicle or test drive it and realize I got no speedometer reading and I get reminded I forgot to reconnect the VSS. I'm also not sure how it would pick up the speed accurately as ABS does not know the size of tire or rear end ratio, unless the ABS has a way of having its own internal equation based on parameters set in the engine because the engine uses a tone wheel teeth count at the tail shaft out put to calculate vehicle speed.