I recently bought a 2000 F250 with a Cummins, and an NV4500 and a ram tcase in it. I am having a heck of a time getting the speedometer working. I have checked wiring diagrams and researched till I’m blue In The face. Basically, the PO deleted the 4Wabs module, which obviously the Speedo isn’t gonna work then. I bought a used module, and connected it, I can communicate with my snap on scanner, and driving I have speed signal from the differential speed sensor. (Nothing from the fronts, they are disconnected) Only codes in the module are for the front sensors. I have no Speedo, and in the pcm, the VSS data reads zero. I have honed out the wires from the abs to the pcm, they’re good, and checked the wire to the overhead console so make sure the signal was getting through the cab okay. And wire tests good.

basically it seems as my used abs module is not calculating and outputting the VSS signal to the pcm, gem, and the Speedo, but it IS receiving speed signal from the rear speed sensor as I can read speed in the data stream. From what I can tell, the pcm is from an auto. It doesn’t seem that the Cummins/manual aspect of the truck should have ANYTHING to do with the speedometer.

ANYONE have any clues? I am out of ideas. Unless the abs or pcm need to be reprogrammed or something.

 

The ABS module doesn't need to work for the speedometer to work, they both get a signal from the rear VSS but they are separate systems. What kind of PCM do you have?