How to: Recalibrate Speedometer with Forscan for 2021 Bronco

[Tricky Dick]

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.

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[rtaylor]

What gearset do you have in yours?

4.7. There should be a parameter called "axle ratio" or something similar in BdyCM if you need to change it.

 

[RustysBronco]

4.7. There should be a parameter called "axle ratio" or something similar in BdyCM if you need to change it.

Got it. I'm curious what bearing the axle ratio has on the tire size value for the speedo. I've got the gearing from a non-sas OB. Plugged in the SAS tire value and it seemed like things were off. Ideas?

 

[Broncola]

@rtaylor thanks for the relearn work around. Did you figure that out yourself?

 

[rtaylor]

Got it. I'm curious what bearing the axle ratio has on the tire size value for the speedo. I've got the gearing from a non-sas OB. Plugged in the SAS tire value and it seemed like things were off. Ideas?

As far as I know, the axle ratio isn't supposed to matter (as long as it is set correctly). Ford typically uses ~97% of new tire circumference (2653mm for sasquatch tires) to minimize error over tire life. But you can adjust the value if your tires are different than the marked size.

@rtaylor thanks for the relearn work around. Did you figure that out yourself?

I tried a few things and found that the PCM service procedure worked reliably. The PCM relearn will probably be fixed in ForScan eventually.

 

[RustysBronco]

Btw thank you!

Will not work in 2.3.46 for those who are using that build and have been unsuccessful.

 

[redone17]

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.

That’s strange. I started at 2698 for 285/75R17 and found the sweet spot to be 2580.

 

[mAtTyG04]

Anyone go from a factory Sasquatch 315/70/17 to a 35x12.5x17? What number did you use to get it nuts on?

 

[Raptor72]

I am a Mac guy. Seems there is no forscan love for Apple? Have any of you purchased a cheap Windows 10 laptop just for forscan? Any recommendations?

 

[balber]

I am a Mac guy. Seems there is no forscan love for Apple? Have any of you purchased a cheap Windows 10 laptop just for forscan? Any recommendations?

Forscan will work on Intel based Macs. If you have a newer Mac (M1 chip) this is built off of ARM architecture and it won't work. You probably were forced to use Windows 11 as there is no supported ARM-based Windows 10/7 build. You can get the software to install but once installed, you double click FORScan and nothing happens.

My suggestion, buy a cheap Windows 10 laptop and go from there. Alternatively you can use the mobile version, but I've never done that. Always felt right to use a laptop.

 

[feralc]

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

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.

thank you very much for this, playing with FORSCAN i found this under

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

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.

thanks for your help, I followed your instructions yesterday and I ran PCM Reset all Adaptations service function and that cleared the PCM 160a DTC code.
two tings:
Today I read DTCs just to be sure there is no DTC and I found this one (but no wrench icon nor warning light on the dash):

PSCM:
Code: U0415 - Invalid Data Received from Anti-Lock Brake System (ABS) Control Module A

Status:
- Previously set DTC Maturing - Not Present at Time of Request
- Malfunction Indicator Lamp is Off for this DTC

Module: Power Steering Control Module

There's no ABS relearn mode but there is ABS Module Reset service, should I had performed this reset as well?? I know the DTC is not present at this time but maybe an "ABS reset" along with "PCM Reset all Adaptations" is necessary to prevent these DTCs to keep appearing??


On another note playing with Forscan I found this under IPMA
"Wheel arch height, left front, mm" and "Wheel arch height, right front, mm" both set to 956, does
I never confirmed this height with the stock tires but my guess is pretty close as my height now with bigger tires is aprox 980 mms to the wheel arch (not the fender flare)
Anyone know what is this value for and what does it do? ,
and also, can anyone with sasquatch package please check what number is there by factory?
Thanks in advance

 

[rtaylor]

There's no ABS relearn mode but there is ABS Module Reset service, should I had performed this reset as well?? I know the DTC is not present at this time but maybe an "ABS reset" along with "PCM Reset all Adaptations" is necessary to prevent these DTCs to keep appearing??

You should be able to reset this from the DTC screen.

On another note playing with Forscan I found this under IPMA
"Wheel arch height, left front, mm" and "Wheel arch height, right front, mm" both set to 956, does
I never confirmed this height with the stock tires but my guess is pretty close as my height now with bigger tires is aprox 980 mms to the wheel arch (not the fender flare)
Anyone know what is this value for and what does it do? ,

This is related to the safety camera. I think it asks you to measure this in the service procedure and you may need to update the value before doing the calibration.

Technically, the camera is supposed to be recalibrated after tire size or lift changes. I don't know if the Forscan service procedure (IPMA - Lane Departure Warning System Camera calibration) works. It may be risky to try if your lane keeping is already working.

 

[feralc]

You should be able to reset this from the DTC screen.


This is related to the safety camera. I think it asks you to measure this in the service procedure and you may need to update the value before doing the calibration.

Technically, the camera is supposed to be recalibrated after tire size or lift changes. I don't know if the Forscan service procedure (IPMA - Lane Departure Warning System Camera calibration) works. It may be risky to try if your lane keeping is already working.

Thanks for the camera calibration info, I am going to leave as it is, it is working just fine right now and even if it is not that accurate I do not really care, I only use the random "pull" as a reminder to pay attention to lanes.
Regarding the DTCs yes I know I can clear them using Forscan, I actually cleared all codes before performing the PCM reset-all-adaptations service function (per your instructions #4 )
and I confirmed all DTCs were cleared (instructions #6), but this morning I connected Forscan (didnt have any warning that a code was generated) and had the PSCM code U0415 (although not present at that moment but logged in the history) and because it is ABS related I was wondering if maybe I should had performed an "ABS reset" just to prevent this from reoccurring.
Thanks

 

[feralc]

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

Just wanted to give an update that PCM relearn option worked for me today, and NO I did not download the latest version released 04/19/22, I used the previous version 2.3.46 released on 02/07/22, so I am not sure why but it did, it is worth a try, and if it doesn't then perform the PCM service reset function

Question for the experts here, If I ONLY change the TPMS value in BdyCM but NOT the diameter, do I need to execute PCM and AWD relearn functions again to prevent a PCM 160A DTC??

I changed my tires to 295/70R18 so I increased the TPMS from 35 to 39 (mimicking sasquatch value) and my speedometer is spot on at 2600 circumference, but after checking tiresize.com/pressure-calculator/ it seems I should use the same 35 psi as my stock OBX tires.

Thanks

 

[Bradley]

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

2440 mm is 31". So using whatever he used as a correction is not right since it's 35" and the tires are most probably not 35".

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