97 F150 speedo cal

[Curious Hound]

So I got new tires on the Fun50 the other day and they are slightly smaller diameter than OEM size. 28.7” vs 29”. Is speedo calibration something I should be able to change with Forscan? 97 F150, 4.6l, 4r70?

I know I bought the cable for my laptop and I’m pretty sure I already installed Forscan. I have just never had a need to play with it until now.

 

[Roert42]

I know the OBDI F-150s the odometer could be adjusted via the digital odometer reset button. I know 97 the year they switched body styles.

 

[fastpakr]

Yeah - I've done the odometer reset button procedure on a '92. For some reason I thought Forscan didn't have access to do speedo cal's on early OBDII Ford's. Been a while since I tried to find documentation on it though.

 

[Curious Hound]

Interesting. I never heard of doing it with the odometer.

might be a moot point. I just did the calculations and figured out it’s only a change if 7 tire revolutions per mile. A 1.03% change. I’ll compare the speedo reading with gps on my phone and see if it’s really enough to worry about.

 

[Roert42]

Forscan has a forum with information on using the advanced version. This link is specifically for changing tire size.

How to use FORScan to adjust tire size - FORScan forum

 

[fastpakr]

Forscan has a forum with information on using the advanced version. This link is specifically for changing tire size.

How to use FORScan to adjust tire size - FORScan forum

Forscan definitely can do it in some cases, but I think this is the sticking point from your link:

Note 1: this article is actual for new vehicles with so called Economized Central Configuration (ECC). ECC means that some memory blocks in BdyCM module of the car are reserved to store parameters that are used by several modules. Tire Size is one of such parameters. Although it has been stored in BdyCM, it is actually used by PCM, TCM, AWD, ABS etc. There is some specific in managing ECC, reviewed below.

My memory is very fuzzy on this, but I think the year when the 'Economized Central Configuration' bit comes into play is a lot more recent. Like the last ten years or so?

 

[fastpakr]

From some of the posts at this link, that capability might be as recent as 2015:

Forscan and Tire Size?

With Forscan , can you change in computer your tire size? Going from 275-55-20 to a 305-50-20, wondering about speedometer and odometer readings.

www.f150ecoboost.net