How to use FORScan to adjust tire size

[antoonio]

So here is my story (didnt knew about this topic when i was dealing with that).
2016 SMax (mk2) has 3 tire size mentioned on the lable. My car has smallest ones (factory stuff) 235 / 55 R17.
Original value 2098 and speedo had about 3-4 kmh higer what gps showed (regular (must be) error in EU).
Ok got info tht changing value makes things better. Ok using, web calculator got new value 2167. Changed it and what happend . On the clock was 90kmh and gps 82??!!. OK changed back. Other day i was doing smth in IPC module and noticed line Speedometer configuration and value was Euro. Changed it to North America and speed was 90 on the clock and gps 88. Hmm, much better. Then i went back to BCM and changed original value 2098 to 2029 (-69 not +69 as i did 1st time). Now cloc was 90 but gps 92. so made come test and now i keep it 2050 what means on 90kmh on the clok is 90 to 90,5 on gps and 50kmh is smth like bit less than 50kmh with gps.
Got that P0160 error too. Figured out what makes this and somehow i did learn car procedure and all is fine.
Soon i will put summer tires and will check again whats going to happen .

[Foobar]

I have 2012 mustang v6 that is about 20% fast on the Speedo. I can’t find the bdycm module in forscan. It’s older so I’m wonder if it’d be somewhere else. Any help appreciated!

[menasco]

I do not have "RELEARN" only RESET for PCM TCM - see attached. I have tried 2746,2770,2780,2799,2800. I'm positive there is a step I am missing,

Is there a number that has worked for similar and maybe 2023 is different? - @willyfly4food - did you change any other settings or just the tire circumference in the Bdy CM ?

Happy to take suggestions or advice from someone with same settings on same year?
Thanks!

I am running into the same problem with a 2024 f350. Were you able to figure it out?

I am using v2.3.59, there is a yt video and he is running v2.3.57.

Billy

[trebron59]

Unfortunately I have not been able to fix the issue. I had Forscan support contacted about it.

They responded:
As soon as you change the tire size, the P160A DTC must appear in PCM and (may be) in other powertrain modules (TCM AWD ABS etc). In this case you have to make the relearn of corresponding module.
If P160A doesn't appear, it means the tire size change most likely has no effect for some reason.

[chad111]

I do not have "RELEARN" only RESET for PCM TCM - see attached. I have tried 2746,2770,2780,2799,2800. I'm positive there is a step I am missing,

Is there a number that has worked for similar and maybe 2023 is different? - @willyfly4food - did you change any other settings or just the tire circumference in the Bdy CM ?

Happy to take suggestions or advice from someone with same settings on same year?
Thanks!

I am running into the same problem with a 2024 f350. Were you able to figure it out?

I am using v2.3.59, there is a yt video and he is running v2.3.57.

Billy

Did you figure out a solution to this?

[03jbeer]

New to FORScan (Version 2.3.59). Have 2023 F250 Platinum Tremor with 37" tires. Followed the YouTube video putting circumference to 2799. Getting P160A:00-2F in TCM. So far haven't gotten a check engine light, but code will not clear.

[chad111]

Rocky Rohde has a great video on you tube for programming. Worked great on my 24 F250.

I'm really struggling with my 21 f150. The TCM isn't listed in my modules. I have also learned that using 2799 is the largest tire size I can get away with on either truck.

Update: was able to program my 2021 F150 for 295 70 18 just fine. I just changed the tire size in MM and did a PCM relearn. All functions such as speed sign recognition, speed limit tolerance and all other Co-pilot functions are working properly.

[sergeT5]

So here is my story (didnt knew about this topic when i was dealing with that).
2016 SMax (mk2) has 3 tire size mentioned on the lable. My car has smallest ones (factory stuff) 235 / 55 R17.
Original value 2098 and speedo had about 3-4 kmh higer what gps showed (regular (must be) error in EU).
Ok got info tht changing value makes things better. Ok using, web calculator got new value 2167. Changed it and what happend . On the clock was 90kmh and gps 82??!!. OK changed back. Other day i was doing smth in IPC module and noticed line Speedometer configuration and value was Euro. Changed it to North America and speed was 90 on the clock and gps 88. Hmm, much better. Then i went back to BCM and changed original value 2098 to 2029 (-69 not +69 as i did 1st time). Now cloc was 90 but gps 92. so made come test and now i keep it 2050 what means on 90kmh on the clok is 90 to 90,5 on gps and 50kmh is smth like bit less than 50kmh with gps.
Got that P0160 error too. Figured out what makes this and somehow i did learn car procedure and all is fine.
Soon i will put summer tires and will check again whats going to happen .

I also have a S-max. Original tires are 245/45 R19, circumference 2208 mm.
The Tire Circumference is set to 2137 in BdyCM (factory settings).
With this, displayed speed is 4% more than actual GPS speed.
I will read again all posts before changing anything!

[Folmsted]

i have a 2013 f150 and changed my tires from 235/75R17 to 285/70R17 , since my BCM didnt offer the 285/70R17 as an option (not listed) i just entered the new circumference value, wrote it to ECU , Did the PCM relearn, but the dtc still will not clear and the speedo is still 3 miles per hour off

[Cfrimm]

Does anyone have the factory Tremor number for tire circumference on a 285/75r18?