FORScan for Changing Tire Size?

[Tx-Tremor6.7]

Has anyone been able to successfully change the tire size on a 2021 without setting a CEL? If so, how did you do it?

I tried to change the tire circumference using FORScan, but it set several DTCs and left me with a CEL.

Module: BdyCm-BCM
Tire Circumference, mm
After doing the math, I changed the value from 2689 to 2934 (36.77” diameter)

I changed the value back, and then cleared the DTCs and CEL. They did not return, so I know this was the issue. Plus, I was able to set several other values correctly without DTCs.

On an interesting side note, the default tire circumference value equates to a 33.68” tire diameter, not a 35” like we have on the Tremor.

 

[Vigilance247]

I really hoped that the YouTube I found would do the trick?

 

[Tx-Tremor6.7]

I really hoped that the YouTube I found would do the trick?

I found a Forscan spreadsheet on one of the super duty forums, but it had a note that said they were working on Table values to get around the CEL problems with tire size changes. It was last updated in March 2021, so this led me to ask on our forum.

 

[CalTremor2020]

I’ve been wondering if you could cheat and change the differential ratio instead of the tire size. That should make the engine rpm match with speed as long as you don’t get a code from the wheel speed sensors. I don’t think it would. They are generally looking for high wheel speed differentials (loss of traction) but I haven’t been able to try it because I still have the stock tires. You’d set the differential ratio to (35/37)*3.55 = 3.35

 

[Vecman]

I found this site explaining how to fix issues after changing a tire size. See if it can help you. I hate driving around making calculations of what my actual speed is.

How to use FORScan to adjust tire size - FORScan forum

 

[speeddev]

Now what did I do??!!

I was trying to use FORSCAN to play with the tire size. I first tried changing the 2689 to 2934 for 37s in the plain English Bdy CM. That immediately gave me the DTC/CEL. I then tried relearning those modules but during the programming the log said "out of range" for the parameter. I kept playing with the Bdy CM plain English and finally figured out that anything below 2800 is accepted, >2801 triggers the out of range. Next I relearned both the PCM and TCM modules. After clearing, I was able to get rid of the "yellow wrench" but still had the CEL. I figured I'd go back to stock--changed the value in the Bdy CM Plain English back to the stock 2689, relearned both the PCM and TCM. Now, after clearing all codes, I'm still getting the PCM DTC:

Code: P0610 - Control Module Vehicle Options Error

Status:
- DTC Maturing - Intermittent at Time of Request
- Malfunction Indicator Lamp is Off for this DTC
- Test not complete

Module: Powertrain Control Module

Code: P0610 - Control Module Vehicle Options Error

Status:
- Pending - malfunction is expected to be confirmed

Module: On Board Diagnostic II

Where am I going wrong? Thanks in advance for your input.

Cheers.

 

[PNW Tremor]

Has anyone been able to successfully change the tire size on a 2021 without setting a CEL? If so, how did you do it?

I tried to change the tire circumference using FORScan, but it set several DTCs and left me with a CEL.

Module: BdyCm-BCM
Tire Circumference, mm
After doing the math, I changed the value from 2689 to 2934 (36.77” diameter)

I changed the value back, and then cleared the DTCs and CEL. They did not return, so I know this was the issue. Plus, I was able to set several other values correctly without DTCs.

On an interesting side note, the default tire circumference value equates to a 33.68” tire diameter, not a 35” like we have on the Tremor.

The dealer took care of it for me.

 

[kirkl]

Now what did I do??!!

I was trying to use FORSCAN to play with the tire size. I first tried changing the 2689 to 2934 for 37s in the plain English Bdy CM. That immediately gave me the DTC/CEL. I then tried relearning those modules but during the programming the log said "out of range" for the parameter. I kept playing with the Bdy CM plain English and finally figured out that anything below 2800 is accepted, >2801 triggers the out of range. Next I relearned both the PCM and TCM modules. After clearing, I was able to get rid of the "yellow wrench" but still had the CEL. I figured I'd go back to stock--changed the value in the Bdy CM Plain English back to the stock 2689, relearned both the PCM and TCM. Now, after clearing all codes, I'm still getting the PCM DTC:

Code: P0610 - Control Module Vehicle Options Error

Status:
- DTC Maturing - Intermittent at Time of Request
- Malfunction Indicator Lamp is Off for this DTC
- Test not complete

Module: Powertrain Control Module

Code: P0610 - Control Module Vehicle Options Error

Status:
- Pending - malfunction is expected to be confirmed

Module: On Board Diagnostic II

Where am I going wrong? Thanks in advance for your input.

Cheers.

How to use FORScan to adjust tire size - FORScan forum

I was able to clear all codes after relearning both PCM and TCM, also clearing DTCs.

 

[NWGATremor]

How to use FORScan to adjust tire size - FORScan forum

I was able to clear all codes after relearning both PCM and TCM, also clearing DTCs.

I tried this a couple weeks back and was not able to clear the codes. Did you follow this line item by line item? I’ve got a 7.3 so curious if diesel vs gas changes anything or something

 

[kirkl]

How to use FORScan to adjust tire size - FORScan forum

I was able to clear all codes after relearning both PCM and TCM, also clearing DTCs.

That's odd, usually a relearn and DTC clear it should be fine. No wrench nor DTC's after the steps. I did go over the 2800 also on my first attempt with errors but went low to 2615 and nailed it up to 70mph then it goes out again to about 2mph difference.