How to: Recalibrate Speedometer with Forscan for 2021 Bronco

[HPNQ420]

Just another testimonial . . . same version, same scan adapter, same successful result. PCM and AWD module DTC codes cleared without issue.

Switched out 315/70-17 OEM Territories to P285/70-17 Cooper Discoverer AT3 4S, used 2525 mm (was 2653) circumference (Thx um . . . @Tricky Mike ?)

and 35 psi (was 39 psi) TPIM settings. Speedo reads 1 mph over GPS reading, perhaps due to minor differences of LT vs P-metric spec. I'm good with it as is.

Took me a little while to get comfortable with maneuvering between screens, but once I figured it out, it was easy. Be patient, and backup the factory settings FIRST! Speakers are next, I appreciate the 6G community for such an informative and valuable resource.

I think the digital speedometer is programmed to read 1 mph over. It was a consistent 1 mph over from 0 to 85 stock and it is the same reprogrammed for my 285/70 17’s (replacing 265/70 17’s) on my Black Diamond.

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[Langwilliams]

OK I made a mess of calibrating the speedometer. I wasn't aware of the check engine lights an the module resets needed. I changed the tire size an had it almost dead on an tried to clear the codes after the little test drive. Forscan wouldn't clear them so I tried my hand held tool an it wouldn't. My brother says just pull the ground for ten minutes. Did that an same story. I found this thread which sounded like the answer but now when I try to run forscan I get red X's with a saying "can't read DTC" an I tried clearing the codes, the lights are on the dash but no codes show up on Forscan.
I tried to run the body module again an it started an stopped an froze up.

I'm thinking my next move is to revert back to as built. The tire size an tpms pressure setting was the only change I made an the body module is the only one I ran.

If no one has an answer I'll try to revert back tomorrow or Friday.

Thanks for any input.

 

[Brian_B]

OK I made a mess of calibrating the speedometer. I wasn't aware of the check engine lights an the module resets needed. I changed the tire size an had it almost dead on an tried to clear the codes after the little test drive. Forscan wouldn't clear them so I tried my hand held tool an it wouldn't. My brother says just pull the ground for ten minutes. Did that an same story. I found this thread which sounded like the answer but now when I try to run forscan I get red X's with a saying "can't read DTC" an I tried clearing the codes, the lights are on the dash but no codes show up on Forscan.
I tried to run the body module again an it started an stopped an froze up.

I'm thinking my next move is to revert back to as built. The tire size an tpms pressure setting was the only change I made an the body module is the only one I ran.

If no one has an answer I'll try to revert back tomorrow or Friday.

Thanks for any input.

Did you get the PCM/TCM relearns run?

Going back to stock might get you back, but usually these relearns are the part that catches folks up on resetting the speedometer.

 

[Langwilliams]

Did you get the PCM/TCM relearns run?

Going back to stock might get you back, but usually these relearns are the part that catches folks up on resetting the speedometer.

I tried an it starts but only runs them a few percent then stops

 

[Langwilliams]

I tried to revert back to stock an it wouldn't load.

Any action I try to take stops and it says "Service procedure has been interrupted"

When I connect an it's loading after it loads every module it says "unable to read DTC"

I'm afraid I'm gonna be paying for this one. It drives normal an it seems everything works, cruise and 4x4 I just have the lights.

 

[Caballo Verde]

Just another testimonial . . . same version, same scan adapter, same successful result. PCM and AWD module DTC codes cleared without issue.

Switched out 315/70-17 OEM Territories to P285/70-17 Cooper Discoverer AT3 4S, used 2525 mm (was 2653) circumference (Thx um . . . @Tricky Mike ?)

and 35 psi (was 39 psi) TPIM settings. Speedo reads 1 mph over GPS reading, perhaps due to minor differences of LT vs P-metric spec. I'm good with it as is.

Took me a little while to get comfortable with maneuvering between screens, but once I figured it out, it was easy. Be patient, and backup the factory settings FIRST! Speakers are next, I appreciate the 6G community for such an informative and valuable resource.

Just switched to these same tires so your success has led to mine! Thanks!

 

[Langwilliams]

If anyone cares I got it back to stock today. I decided to try driving it a few days to get some "drive cycles" on it then try rerunning the bcm an put the stock tire size in. did a reset to the pcm awd an all the lights cleared an it was back to normal with the speedometer off.

Tomorrow I'll try to write the corrected tire size, run awd relearn, clear dtc codes an a pcm reset. I think that's the process from reading all this multiple times!

 

[my_hero_nero]

Use the PCM service function instead of the PCM relearn. The PCM relearn doesn't work.

UPDATE: on new Forscan versions (2.3.52+), " PCM Module initialization/relearn vehicle data" is reported to work.

Detail:
1- I used FORScanSetup2.3.47.test20220221 (version that supports MY2022 goat modes) with OBDLink EX. You will also need a FORScan demo license.
FORScanSetup2.3.47.test20220221.exe

2- Set front/rear TPMS and tire size in BdyCM. For KM3 37x12.50R17D on sasquatch wheels, use 35psi and 2760mm. For sasquatch stock tires and wheels, use 39psi and 2653mm. Tire circumference cannot exceed 2800mm. DTC's will be set in 2-3 modules that will need to be fixed.

3 - To fix the non-PCM DTC's, run the AWD relearn. Don't run the PCM relearn (it doesn't work).

4 - Clear the DTC's. All should be cleared except PCM.
5 - Run the PCM reset-all-adaptations service function. This will fix the size mismatch and also clear the PCM DTC. It will relearn the engine/trans/fuel adaptations over time while driving. UPDATE: on new Forscan versions (2.3.52+), " PCM Module initialization/relearn vehicle data" is reported to work.

6 - Confirm all DTCs are cleared.

7 - Install a free speedometer app with tenth-mph readout on your phone and testdrive to confirm speed is within 0.5mph at 60mph cruise control. For new tires, the actual speed should be a little higher than speedo. For worn tires the actual speed will be a little less.

Will this still work for 2024s?

 

[rtaylor]

Will this still work for 2024s?

It should, but use the latest forscan version.

 

[DesertMike680]

Wondering what the dealership costs just to adjust to slightly bigger tires for how ever many hours of work. Going to give my dealership a call. Really dont feel like screwing with this in Forscan. Audio adjustments was easy regardless.

 

[Air Biscuit]

Wondering what the dealership costs just to adjust to slightly bigger tires for how ever many hours of work. Going to give my dealership a call. Really dont feel like screwing with this in Forscan. Audio adjustments was easy regardless.

I was thinking the same thing…

 

[BoomGator]

Wondering what the dealership costs just to adjust to slightly bigger tires for how ever many hours of work. Going to give my dealership a call. Really dont feel like screwing with this in Forscan. Audio adjustments was easy regardless.

I was thinking the same thing…

I had 35s installed on my ‘24 Black Diamond today and asked that very question. The service writer seemed confused, then called a manager or something. He said they “had to order a part to install”—which was $250–plus the hour of labor. I said thanks but no thanks.

 

[dannterepka]

Hey guys,
changed the tire size on a 24 Outer banks bronco. Reset bcm. but no PCM but there is no AWB or TCMM module to reset. Using latest forscan.

now I have a service 4x4 and when iread DTC code i have ABS U0403 code show up.

anyone else have this problem?

 

[B22-2023]

Thanks for everyone's work on this. I was prepared to dig in after bumping up to 315s but it's only off 1 mph at 70 so I'm leaving it alone.

As another data point, mine was factory set at 2525mm with 285/70/17s. This sounds way too small for 315s but I'm not arguing with what works.

I had a lower than expected number too. On BFG KO2 315/70-17, I measured the tire radius today and did the math; 2633 mm circumference. I had originally entered 2745 mm just using the tire size, and speed was off. Loaded 2633, relearned the other modules to clear codes, and it’s dead on.

 

[Audiomate]

I have a Badlands Bronco on 35s and today sent it to the dealership to have the speedometer corrected using Forscan. A few hours later, I received a "Powertrain Malfunction" message on my FordPass app.

Shortly after, the dealer called me and explained that their technician was unable to adjust the speedometer because it was generating an error message that was disabling my 4x4 system. They had to revert the settings back to how they were before.

I searched through various threads but couldn't find anyone who has experienced a similar issue. My Bronco is still at the dealership, and I'm now worried about the possibility of my 4x4 system failing while I'm out wheeling.

Has anyone encountered a similar issue? Is there a solution to this?

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