FORScan Speedo Calibration for larger tires

[hogsrear]

Tried searching but haven't had much luck. Has anyone (non Forscan users) had luck getting the dealership to do this calibration? I am ready to swap for larger tires and want my speedo/odo readings to still be correct. To me this would make more sense than buying the scan tool, assuming it's something that would be really easy for them. But maybe not?

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[TKDMasterV]

Tried searching but haven't had much luck. Has anyone (non Forscan users) had luck getting the dealership to do this calibration? I am ready to swap for larger tires and want my speedo/odo readings to still be correct. To me this would make more sense than buying the scan tool, assuming it's something that would be really easy for them. But maybe not?

I asked the dealer on two separate occasions, two separate service guys and was told both times they were no longer allowed to do it.

 

[hogsrear]

I asked the dealer on two separate occasions, two separate service guys and was told both times they were no longer allowed to do it.

Strange. I guess it's still worth asking my local dealer, especially if I have them do the front shocks and putting on the larger tires anyways. Also saw someone above mention this (years ago now) but will gladly pay to rent someone's calibrator!

 

[Mustangski]

Have a 2021 Ranger FX4, original tires were the Hankook ATM 265-60/R18's. Recently bought some Tremor take-off rims with the factory General Grabber ATX 265-70/R17 tires. I have forscan and started the process to get the speedo accurate, however when I checked cruise control against a speedo app on my Iphone 8 it was almost exact. Took several test drives from 3 to 30 miles at a shot and only averaging .03-.06 miles farther per mile on my speedo app versus the truck. Basically the MPH is exactly on until about 55-56 MPH, then only off by 1 MPH. Since the online tire calculator shows a 3.6% increase in circumference, I'd assume the factory speedo was a good bit off from the start. Honesly don't think I'll adjust it at all since its so close.

Anyone else notice this when they increased tire size?

 

[THLONE]

You are never going to get a perfectly accurate speedo reading at all speeds. The tires get larger the faster you go.

 

[Mustangski]

I get that there are several variables to gaining accuracy on speedometers, and not looking for perfection. I was just a bit surprised that the larger tires seem to have made the speedo more accurate. It wasn’t a large jump in size, I would recommend checking your speed with GPS before purchasing all of the stuff to use Forscan especially if you only plan to use it for tire circumference.

side note, I called local dealer as well. They will not adjust the speedometer, so it seems you’d have to use Forscan or purchase a tuner to adjust.

 

[Ronbo]

Can anyone with a Tremor and Forscan, who is running the Grabber ATX 265/70/17 tires, check what the mm setting is in the BdyCM module under “tire circumference “?

 

[Cane777]

Anyone have the tire circumference for a 33x12.50r17 m/t? I am slow by 1/2 mile with 2490 in forscan.

 

[Sanctus Rimor]

You can get tire circumference here

https://tiresize.com/comparison/

 

[GTGallop]

Not sure how to fix it but here is what I found on the U0422 code.

SCCM U0422:00 Invalid Data Received From Body Control Module: No Sub Type Information This DTC sets when SCCM recieves an invalid message from the BCM.

It looks like the value is also stored within the SCCM or maybe there are only a few default values allowed? Maybe there is a way to do an SCCM relearn or change the value in the SCCM to match? Not sure but thought this might help as I hadn't seen anyone mention the steering column control module with this code.

I will probably put larger tires on my truck some day so hoping maybe someone figures this out.

Reviving a Zombie Thread Here... ?‍

Had my neighbor come by today with his Forscan. We made the change to the BCM and got the error above. Looks like we need to adjust PCM and TCM too. Question is where and what setting do we need to get to to make the change or to force it to learn the new values?

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