2003 T&C, 3.8, 4-speed auto, with correct tire size

My speedometer displays approximately 5 mph slower than actual speed. I have checked this with gps during several trips totaling 2000 miles(+/-). This is also effecting the odometer. Every 200 miles the van travels it displays 188 (+/-).

I searched this site to find other speedo problems but none like mine. The other's seem to be worse than mine. Like not working at all or jumping around. Advice for these problems focused around the "Automatic Trans. Speed Sensor Input & Output".

Would replacing the ATS Input & Output sensors correct my issue or should I repair/replace something else?

Thanks for your time!

 

Many moons ago I had a VW that indicated 5 mph low. Dealer showed me an official looking document (not VW Corp) that stated it can read up to 7 mph low without having to repair it. They didn't. I lived with it.

- 3rd generation vans had a cluster self test you could do to verify all the gauge indications were within spec. Not sure how to do it on your 4th generation van.
- Might have the transmission pinion factor checked
- If you change anything it would be the output speed sensor. That is the "sender" for the speedo. Anything beyond that turns into big bucks.

 

Thanks again Raptor