Using Forscan to update tire size

[domct203]

I've been searching the forum for info on updating the tire size for my '02 XLS using Forscan. I'm finding a lot of different threads on the general subject, but nothing specific to the 3rd Gen.

Is this even possible on the 3rd Gen's? I'd like to correct the Speedometer, Odometer, and anything else that relies on correct tire size info (tranny shifts, ABS, etc).

Thanks,
Dom

 

[Argentimage]

to what vehicle and model year do you see this as possible?

modern as in last 5 years its possible but no nothing about doing it, other than its programmed when the vehicle is finished. I doubt the Gen 3 was that advanced, its almost 20 years ago.

 

[domct203]

to what vehicle and model year do you see this as possible?

modern as in last 5 years its possible but no nothing about doing it, other than its programmed when the vehicle is finished. I doubt the Gen 3 was that advanced, its almost 20 years ago.

Precisely why I’m asking.

Is this even possible on the 3rd Gen's?

Do you have any experience with Forscan?

 

[Argentimage]

no I do not know this tool. pls forward some links.

I know from a top level how this is all configurable at end of assembly line in 2019...and the last ten years or so.

 

[domct203]

If you search here on the forum you’ll find info on using Forscan to tweak the BCM / ECM. I know that earlier models have less modules to access, but I’m hoping tire diameter (or revs per mile) is one of them on the 3rd Generation Explorer.

FORScan forum - Index page

 

[Argentimage]

Today it would not be in the bcm
Not sure back then
I would expect pcm configuration
Cluster table maybe because that’s where the tpms messages
I recall most of this was hard coded back then

Not a lot of guys left that designed these

 

[Mbrooks420]

I doubt this is hard coded and not changeable. Possibly not with forscan, but the manufacturer would not inhibit themselves from making changes like this, as several manufacturers have made these exact changes to make their ABS systems more effective (safe).

 

[Argentimage]

Today these are end of line configured into 15 different modules

You flip bits

Back then it was tables in the hard coded software

 

[Mbrooks420]

I program things for a living, I understand how it’s done. None of the programming is truly unmanipulatable. It might require a flash, but it’s not set in stone.

 

[CDW6212R]

That's my thoughts about it also. I haven't read of anything possible with any older PCM's, besides people writing that in new programs it can be adjusted. I'd like to tweak it a bit also, in the 1st and 2nd gens, the most accurate tire size is 30.0", not the more common 29" that most came with. I don't mind avoiding speeding tickets, but I'd rather have accurate speed readings, as well as true fuel consumption data.

 

[domct203]

SCT claims that their X4 will adjust for tire sizes on the 3rd Gens, so I'm hoping FORscan will.

SCT

 

[Phisherman]

My X4 works, with a custom tune, to adjust tire sizes. The stock X4 tunes did not work with my 2005. Unleashed tuning is awesome! Torrie will fix you up good over there.

 

[15Limited]

OP...did you find your answer? If not, try the FORScan website/forum...they have a lot of info there on which vehicles it will work on.

FORScan forum - Index page

 

[domct203]

OP...did you find your answer? If not, try the FORScan website/forum...they have a lot of info there on which vehicles it will work on.

FORScan forum - Index page

I have a similar post there asking the same questions with no reply.

I really don’t want to spend $400 on the SCT tuner just to adjust tire size. I realize that there are other things I can do as well, but I’m happy with the performance of the truck, and don’t want to push the motor/transmission.

For me, if I have to spend that kind of money, I’ll just change axle gears, which would give me more off road benefits anyway.

 

[bbrown0414]

Did you ever figure this out? I am getting ready to go from the stock 235/70r16 to a 265/70r17 on my 04 xlt 4wd and would like to fix the speedo.