Correct your speedometer error - no flash or tune required

[Spart]

Your entry looks good to me, but the way to know for sure is to check the speedometer against GPS!

No idea on the DTC's. Doesn't look like anything serious but I'm no expert. What you said about the tail lights makes some sense, most newer cars are able to detect when a light is out.

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[Jmeo]

Thanks very much for this thread and your help :cheers:

 

[tedj101]

Many, many thanks for this information! This is a great help. It will make changing tire sizes a non-event...

<TED>

 

[earlingy]

Can you use this method to change the front tire size for ABS and traction control?

 

[Spart]

Can you use this method to change the front tire size for ABS and traction control?

No, this is for the speedometer and odometer. What issue are you having?

 

[earlingy]

Well, ABS and traction control look at your tire speeds. If you were to change sizes, those systems are getting an incorrect reading on current tire speeds. I want to change sizes but not mess with ABS or traction control. Seems like it'd matter a little more if you changed front and rears different amounts, say, from a regular GT to PP wheels/tires.

 

[Spart]

Well, ABS and traction control look at your tire speeds. If you were to change sizes, those systems are getting an incorrect reading on current tire speeds. I want to change sizes but not mess with ABS or traction control. Seems like it'd matter a little more if you changed front and rears different amounts, say, from a regular GT to PP wheels/tires.

I'd have to agree on changing the front and rear different amounts, but I haven't heard of anyone having problems? Not that I've gone looking...

 

[earlingy]

I'd kinda like to go to a square setup on my GT PP. I also haven't heard of anyone having issues but I'm a paranoid/OCD engineer so...

 

[Spart]

Looking at some as-builts I have on hand, my GT PP differs on several lines in the ABS module (760) from a GT without a PP.

I can't make heads or tails of the differences though.

 

[solodogg]

can we make this sticky? This could be extremely helpful for those running non-oem tire sizes.

 

[Ingot2015]

would this work for rear gear swaps?

 

[zuki_dan]

would this work for rear gear swaps?

Should be a different memory block in the BCM for gear swaps. I don't know that anyone has confirmed it working yet but it should work. Check out the AS built thread in the DIY forum sticky.

As Built thread

 

[law242]

shouldnt the dealer be able to fix this? i mean cummon we spent good money on these cars.

 

[Spart]

Should they? Of course, but nonetheless this thread must exist. Don't complain here, complain to Ford.

 

[RubyRed15]

So we've finally figured out how to correct speedometer error (if your car is just off from the factory or you've changed tire sizes.)

Any idea if a similar method would work to correct the difference between the main speedo and the set speed displayed for cruise control?

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