Correct your speedometer error - no flash or tune required

Spart · Oct 21, 2016

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.

Jmeo · Oct 21, 2016

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

tedj101 · Oct 25, 2016

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

<TED>

earlingy · Oct 25, 2016

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

Spart · Oct 25, 2016

earlingy said:
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 · Oct 25, 2016

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 · Oct 25, 2016

earlingy said:
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 · Oct 25, 2016

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 · Oct 25, 2016

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 · Nov 15, 2016

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

Ingot2015 · Nov 15, 2016

would this work for rear gear swaps?

zuki_dan · Nov 15, 2016

Ingot2015 said:
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 · Nov 25, 2016

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

Spart · Nov 27, 2016

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

RubyRed15 · Nov 27, 2016

Spart said:
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?

Correct your speedometer error - no flash or tune required

Spart

Well-Known Member

Jmeo

You said member ;)

tedj101

Well-Known Member

earlingy

Well-Known Member

Spart

Well-Known Member

earlingy

Well-Known Member

Spart

Well-Known Member

earlingy

Well-Known Member

Spart

Well-Known Member

solodogg

Well-Known Member

Ingot2015

Well-Known Member

zuki_dan

Well-Known Member

law242

Well-Known Member

Spart

Well-Known Member

RubyRed15

Ok, so it's blue.