stevieb_wv

Has anyone successfully used Forscan on a 2013 to calibrate the speedometer for larger tires?
I have tried all of the pre-canned settings, plus added custom HEX data per the calculator I found online, but nothing seems to make a difference.
I have read that it can be successfully done with a tuner which leads me to believe that it should be able to be done with Forscan.
No matter what setting I use, I'm still 3 mph off.
The data I'm changing in in the BCM line 726-45-01 which I have verified it does change when using the pre-canned settings.
Any help would be appreciated.

Spiky

No, nobody has figured it out yet. There have been several people with the EXACT same effort/results as you.

RLXXI

Forscan much like Ford's own IDS is incapable of changing tire size even though the option is in the software on both (at least the version of IDS that I have any way), I used an SCTx4 programmer to dial mine in when I went from 30 to 35" tires.
.

jdunk54nl

Actually you can (it is documented in my spreadsheet in my sig too), I have done this using Forscan before I bought my tuner. The only issue is you might get a BCM DTC depending on if your PCM and your BCM don't match up (you can only change your PCM via tuner).

Go to 726-45-01 xxxx **** xxxx and then use this spreadsheet for your size and change the *'s with the hex code. (FYI the hex is your tire circumference in mm)
https://docs.google.com/spreadsheets...EqU/edit#gid=0

stevieb_wv

This is exactly what I did, plus I also tried the pre-canned sizes just for fun. Nothing changed the speedometer.

jdunk54nl

So, step by step, tell me what you did using forscan and how were you checking your speed? I use the waze app and it always matches up with the roadside radar detectors.

stevieb_wv

I changed 726-45-01 **** ABCD **** to OA3B per the calculator. Wrote the change.
Tested by using SpeedBox GPS speedometer and another Speedometer app that I don't remember the name of on my phone with cruise control set on 70.
3 MPH off before and after making the change. Switched it back, then used the pre-canned tire sizes in Forscan, tried every size listed, writing with each one. No changes whatsoever.
I also tried using the speedometer difference portion of the calculator with 70 set as the speedometer and 73 as the GPS value, but still no change.
Supporting what Spikey and Rnlcomp said above, I have found multiple posts on multiple forums with the same results as mine. The change is accepted, but the speedometer doesn't actually change.

jdunk54nl

So you have 295/60/r20 tires? And you hit write, approved the checksum error and verified that the new asbuilt said 0(zero)A3B


Edit* Did you put zero or O (oh). It should be a 0 (zero), Hex does not have an o (oh)

stevieb_wv

Yes, 295/60-R20
Yes Sir. That's exactly what I did.
It was a Zero. I am familiar with Hex. Typo on my part above.

jdunk54nl

Did you try the gps off version the calculator in the link I sent you. If your speedo is reading 70 but you are going 67 via gps. Change your line to 09CB