i own a 2003 dodge neon sxt with 135k miles on it,
i had a code for the output speed sensor so i replaced it with a dealership one then my speedometer stopped working, when i press the gas the gas guage goes down to empty then i hit the brake and it goes up to half a tank, also it isnt tracking miles anymore on neither the trip or the total mileage, whats going on? i have been testing for bad grounds all over the place and cant find a bad one, unless its somehow my battery witch works fine starting and running the car. NOTE: the speed sensor code started popping up after i changed the upper motor mount, just mentioning it incase..

 

my wife just bought the car and I have changed out the speed sensors in and out. Both of them. Speedometer still not working. It keeps engaging the check engine light and prohibiting from getting a Texas inspection sticker. I have checked all the wiring and cannot find a problem. the odometer is lit up but stuck at 142000 miles and is not registering miles. temperature gauge is working fuel tank gauge is working. I have also removed the cluster just to make sure everything look right and put it back in. All looks well. Someone please help As I am under the hood right now. If you know of something and can text me please do at 936-443-7247 Thanks

 

have same issue but I can get my inspection I'm in Killeen tx I heard the problem is in the cluster its self and I have a few extra funny isues like my radio cuts out when I open the doors

 

Sounds like your bcm (body control module) is having issues. Replace the realy for it or fuse