2025 Bronco Badlands - FORScan Tire Circumference Causing Configuration DTCs?

[bfoster]

I'm hoping another 2025 owner can help verify something.

Vehicle:

• 2025 Bronco Badlands/non-SAS
• Factory HOSS suspension with 1.5" Fabtech level
• Motegi MR150 Trailite 17x8.5 +18 wheels
• Mickey Thompson Baja Boss A/T 35x12.50R17 tires

Factory BCM values:

• Tire Circumference: 2525 mm
• TPMS Placard: 39 psi

With the Bronco completely stock (except suspension/wheels/tires), I have:

• No DTCs
• No warning lights
• FordPass reports no issues

My speedometer is approximately 2 mph low at 45-50 mph compared to GPS (45 indicated / 47 GPS).

I started trying to correct the speedometer.

Attempt #1

• Changed BCM As-Built tire value (726-15-01)
• Changed plain-text Tire Circumference
• Result:
  • RCM U2300
  • PSCM U2300
  • AWD U0422
  • Airbag light
  • FordPass restraint warning

Restoring my original BCM As-Built backup immediately cleared all faults.

Attempt #2
I restored the vehicle to stock and then changed only:

• BdyCM Tire Circumference: 2525 to 2650
• TPMS placards: 39 to 30 psi

I did not modify As-Built this time, only the plain text.

Immediately after writing:

• PCM P160A
• AWD P160A

Clearing DTCs did not help—they returned immediately.

As soon as I restored Tire Circumference back to 2525, the P160A codes disappeared.

Changing only the TPMS placards does not appear to generate any DTCs.

At this point, everything is back to stock and the Bronco has:

• No DTCs
• No warning lights
• FordPass clean

My question
Has anyone with a 2025 Bronco successfully changed Tire Circumference using FORScan?

If so:

• Did you modify only the plain-text Tire Circumference?
• Did you also modify As-Built?
• Did you have to run any relearn procedure besides PCM/AWD?
• What final Tire Circumference value are you using?

I'm specifically looking for 2025 model year experience since the behavior seems different from what I've found in earlier Bronco threads.

Thank you all for any help you can provide. I'm just not sure at this point if I am doing something wrong, Ford changed something on the 2025 models or if they've made it so you have to buy and use ProCal.

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[Jason N]

After you change values you gotta do an ABS initialization. Then clear all codes. That should solve it. ABS system has to recalibrate to the new tyre size. That’s what’s throwing the codes.

 

[Ducati1098]

You have to relearn vehicle data on the AWD and PCM after changing tire circumference

 

[bfoster]

Perfect! Thank you. I will try this in the morning.

 

[bfoster]

That did the trick! Thank you again. Now we'll see if I chose the right tire circumference after a test drive. All of this is just experimenting at this stage because I grabbed the ProCal tool & tune last night.

 

[bfoster]

2650 tire circumference was pretty much spot on. The speedo registers maybe .25-.50 higher than than the GPS now. For the most part they match right up. I will be curious to see what the values are after using the ProCal.

 

[shaw]

I'm hoping another 2025 owner can help verify something.

Vehicle:

• 2025 Bronco Badlands/non-SAS
• Factory HOSS suspension with 1.5" Fabtech level
• Motegi MR150 Trailite 17x8.5 +18 wheels
• Mickey Thompson Baja Boss A/T 35x12.50R17 tires

Factory BCM values:

• Tire Circumference: 2525 mm
• TPMS Placard: 39 psi

With the Bronco completely stock (except suspension/wheels/tires), I have:

• No DTCs
• No warning lights
• FordPass reports no issues

My speedometer is approximately 2 mph low at 45-50 mph compared to GPS (45 indicated / 47 GPS).

I started trying to correct the speedometer.

Attempt #1

• Changed BCM As-Built tire value (726-15-01)
• Changed plain-text Tire Circumference
• Result:
  • RCM U2300
  • PSCM U2300
  • AWD U0422
  • Airbag light
  • FordPass restraint warning

Restoring my original BCM As-Built backup immediately cleared all faults.

Attempt #2
I restored the vehicle to stock and then changed only:

• BdyCM Tire Circumference: 2525 to 2650
• TPMS placards: 39 to 30 psi

I did not modify As-Built this time, only the plain text.

Immediately after writing:

• PCM P160A
• AWD P160A

Clearing DTCs did not help—they returned immediately.

As soon as I restored Tire Circumference back to 2525, the P160A codes disappeared.

Changing only the TPMS placards does not appear to generate any DTCs.

At this point, everything is back to stock and the Bronco has:

• No DTCs
• No warning lights
• FordPass clean

My question
Has anyone with a 2025 Bronco successfully changed Tire Circumference using FORScan?

If so:

• Did you modify only the plain-text Tire Circumference?
• Did you also modify As-Built?
• Did you have to run any relearn procedure besides PCM/AWD?
• What final Tire Circumference value are you using?

I'm specifically looking for 2025 model year experience since the behavior seems different from what I've found in earlier Bronco threads.

Thank you all for any help you can provide. I'm just not sure at this point if I am doing something wrong, Ford changed something on the 2025 models or if they've made it so you have to buy and use ProCal.

Interesting findings. Since restoring the original tire circumference immediately clears the codes, it almost seems like Ford added additional validation on the 2025 models. I haven't seen many confirmed reports of 2025 owners successfully changing the tire circumference through FORScan alone. It would be great if someone with a 2025 could confirm whether ProCal is now required or if there's an additional calibration/relearn step that's missing. Please keep us posted if you figure it out, it'll definitely help others running 35s.

 

[bfoster]

Interesting findings. Since restoring the original tire circumference immediately clears the codes, it almost seems like Ford added additional validation on the 2025 models. I haven't seen many confirmed reports of 2025 owners successfully changing the tire circumference through FORScan alone. It would be great if someone with a 2025 could confirm whether ProCal is now required or if there's an additional calibration/relearn step that's missing. Please keep us posted if you figure it out, it'll definitely help others running 35s.

Hey @shaw, see above. Relearning PCM and AWD cleared all codes after making the change.

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