How to: Recalibrate Speedometer with Forscan for 2021 Bronco

[Bronc-Itus]

I think this is a first. Could be a useful video for all those swapping to larger tires immediately.

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[Toccoa]

Very cool. Thanks for sharing.

 

[imnewtothis]

Silver lining to not having my Bronco yet: people are coming out with answers to every question I have so damn quickly

 

[George Ellis]

I remember reading about this in they 2017+ Super Duty forum. His calculated actual mileage was different than the stock number from the computer. So he changed the bias to fix it. So yes, great adjustment. And kudos to Ford for reusing computer code so that Forscan can do this easily.

Found it. So this fixes fuel calculation.

Correcting the display MPG for better accuracy - Ford Truck Enthusiasts Forums (ford-trucks.com)

 

[lakesinai]

I think this is a first. Could be a useful video for all those swapping to larger tires immediately.

I'm not sure I'd want to do this myself, especially since after he changed tire size and tpms settings, he got check engine lights and had to go back and reset the AWD Settings! What else could go wtong? BUT, how much should this cost at a dealer? Do dealers know how to do this? And does this have any effect on the Warranty?

However, its nice to know what Im asking a dealer to do!

 

[Beach_Bum]

I'm not sure I'd want to do this myself, especially since after he changed tire size and tpms settings, he got check engine lights and had to go back and reset the AWD Settings! What else could go wtong? BUT, how much should this cost at a dealer? Do dealers know how to do this? And does this have any effect on the Warranty?

However, its nice to know what Im asking a dealer to do!

With regards to doing yourself, it is imperative that you save the default profile before making any changes. The guy mentions it, but doesn't put the emphasis that it deserves. Having the default profile is your safety net. Make whatever changes that are needed. If there are problems, just restore the default.

 

[Jsullivan]

I think this is a first. Could be a useful video for all those swapping to larger tires immediately.

Great info here. I have my AT3XLT 285/70R17 mounted on Ultra Rims, just no Bronco yet. I will definitely favorites this thread.

 

[nminus1]

I have to chuckle everytime I hear Forscan it seems like a combination of foreskin and Fortran (one of the first computer programming codes) why didn't they just call it FORDSCAN??!!

 

[BroncoBoy22]

Awesome thanks for sharing! If you get time can you check to see if there’s an option to enable a fog light button?

We found out the wiring is there for the fogs (even when they’re missing like on the mod bumper). If it can be enabled on Forscan then all that would be needed is a switch and some aftermarket lights

 

[Contact]

Just make sure after you change the tire size to force the TCM and PCM to relearn and do the reset of the DTC, then you should not have any error messages:

13. Now we have discrepancy between tire size values known by PCM and TCM and new value stored in BdyCM. So we have P160A DTC in TCM module and P0610 in PCM module:

14. In order to remove the discrepancy, we need to force PCM and TCM to “learn” the new value from the ECC. We can do it using Module Initialization/Relearn vehicle data functions for PCM and TCM module:

Note: some cars may have other modules that require this operation, for example AWD, SOBDMC.

15. After running the Relearn functions, we need to reset the DTCs:

 

[HypebeastDad]

My tires are 35/12.5R17 I got 2791 for the circumference. Am I right guys?
I’m going from base tires.

 

[redone17]

Awesome thanks for sharing! If you get time can you check to see if there’s an option to enable a fog light button?

We found out the wiring is there for the fogs (even when they’re missing like on the mod bumper). If it can be enabled on Forscan then all that would be needed is a switch and some aftermarket lights

That’s great news that the wiring is there! There is a dedicated Forscan thread. I’m sure once the spreadsheet is created it will be posted there. Some have been using the latest F150 doc. I’m about to make a few mods today.

What would you have to change on the computer end? Isn’t it just an on/off switch? I’ll defiantly be looking to do this instead of taking up the extra AUX switch.

 

[Contact]

My tires are 35/12.5R17 I got 2791 for the circumference. Am I right guys?
I’m going from base tires.

https://tiresize.com/calculator/

 

[Razorbak86]

My tires are 35/12.5R17 I got 2791 for the circumference. Am I right guys?
I’m going from base tires.

Tarikh, most 35s aren’t exactly 35.0” in diameter. For example, Sasquatch tires (LT315/70 R17) are 34.4” diameter, so the circumference for that tire would be 2741 mm. Not a big difference between 2741 and 2791, but it’s still smaller. So be sure to use your exact tire diameter, and not the nominal diameter marketed by the tire maker. Might as well be exact, if you can.

Source: 2021 Bronco Factory Tire Size & Wheel Size Comparisons (Circumference, Diameter, Height, Width, Bolt Pattern, Center Bore)

 

[lakesinai]

My tires are 35/12.5R17 I got 2791 for the circumference. Am I right guys?
I’m going from base tires.

From my research in general, each Manufacturer could be a little different, but maybe not enough to matter.

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