Reprogram speedo @ dealerhip. W/ custom tunes loaded.

[fharen]

I changed tire size (moved down a little closer to stock) and need to get my speedo reprogrammed at the dealership.

I am running Matt's SRL+

Do I need to return the truck to stok before going to dealer?
Will I need to get an updated tune after going to dealer?

[HeavyAssault]

What are the current PCM/FICM strategies?? I don't recommend letting the dealership do any form of programming. You can use an up to date SCT SF3 to adjust the speedo.

If you go to the dealer return the truck to stock.

[muddy650]

Prolly be best just to get with Matt and get him to write you another tune that will correct your speedo. A tune shouldnt cost more than the dealer doing it.

I may be wrong but I think that is why the tuner needs the tire size for the custom ones!

If you take your truck to the dealer with a tune loaded it will mre than likely be wiped out and you will also lock your SCT up because it will still be married to the way the truck was!

[Tuscany]

Sct will not reset your speedo. It only adjusts the shift points based on tire revolutions per mile.

[HeavyAssault]

Works on my 2006...guess you got an old one.

[Tuscany]

No I have the sf3 I have t updated the firmware yet but it has never been able to change the speedo.

[HeavyAssault]

Before I can even load a tune it asks if I want to change the tire revs. I can adjust mine around pretty easily. What you really need is the actual measurements for the tire revs. Measure the distance in inches it takes to roll the tire one full revolution. Then divide the inches in a mile by that number. This is a good starting point to correct the speedo. I got mine to within 1 MPH based off of GPS running 35" Toyo ATs.

[wagner22]

Originally Posted by HeavyAssault

Before I can even load a tune it asks if I want to change the tire revs.

Ya my X3 asked the same thing before I loaded the tune. I didnt mess with it tho, im only 2 mph off

[bwmtnbiker]

I had ford do mine before I loaded any tunes. Then again Vivian said that the strategies I had were absolutely ancient and she could do a lot more for me if I went and got the most up to date ones. So I had them adjust it while they were there and they can only adjust up to a 35" tire so it helped but I have basically 37s so mine is still off. My SCT gives the option to change revs too but I have not played with it.

Definitely go back to stock before you go back to the dealer, no matter what you are doing there. I hear they like to update strategies without asking people.

[Tuscany]

Mine doesn't ask me to change the tire revs it gives me the choice to adjust options but it hasn't ever changed the speedo when I set the revs per mile.