Hello I'm new to the forum life so please fogive me if this is posted in the wrong area....... I own a 2010 Xd 5Speed and i just got back from a road trip of 1,600 miles and the problem im having is that my speedometer is not correct with the speed im going, I noticed this once i got off the highway and was cruzing at 55, when my speed reads 40mph im actually doing 30mph and 55mph needs to read 65 etc. so my tac is off by 10mph. Any help would be greatly appreciated letting me know what could be the issue with this. Im just really puzzled as i haven't had any issue with my Xd at all... Thanks ......

 

Wrong diameter tires. What size tire is on the car right now? What does the door jam say it should be?

 

On the car right now are 205/60/16 what are supposed to be on the car according to factory are 195/60/16..... I have been runnung the 205's for 8 months without any issues and after this trip is when my tac was messed up

 

how exactly are you checking your speed?

 

first i used my Gps then i knew a couple speed traps and both were correct with my tac

 

try disconnecting the battery, wait about 30 seconds and reconnect it. Mine did the same thing when I removed the gauge cluster to swap the led's.

 

I'll try that today disconnecting the battery Thanks......