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Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Thu Mar 18, 2021 3:21 am
by Fresh_1
I tried about 20 times today to configure a new tire size in my 2019 F150, and I'm not having any luck. I've tried multiple sizes, I tried adjusting the values directly in 726-12-01 using multiple different known good values and values from the spreadhseet tool, and I tried changing the tire circumference. In every instance, I used the relearn function for both the PCM and TCM, but stull get a U0422 error in the PCM. I switch it back to stock and use the relearn function and the error code is gone and everything is fine. I can't figure out what I'm doing wrong. These are the steps I've been following:

1. Launch Forscan and connect to truck with ignition on, but truck not running.
2. Click on the Chip icon.
3. Click on "BdyCM (AS BUILT format)"
4. Click on the Play icon on the bottom.
5. Enter values for ABCD in 726-12-01 XXXX ABCD XXXX
6. Click "Write"
7. Turn ignition of and back on and click "ok" in the prompt
8. Click on the stop button, aka "Stop Service Procedure" button
9. Click on "PCM Module initialization/relearn vehicle data"
10. Turn ignition off when prompted, click "ok"
11. Turn ignition on but don't start the vehicle when prompted, click "ok"
12. Click on "TCM Module initialization/relearn vehicle data"
13. Turn ignition off when prompted, click "ok"
14. Turn ignition on but don't start the vehicle when prompted, click "ok"

At this point I'm still getting the PCM error code, even if I rest the DTCs and check them again.

I also tried the following:

3. Click on "BdyCM"
4. Click on the Play icon on the bottom.
5. Find the entry for Tire Circumference and enter in the new value
6. Click "Write"
7. Turn ignition of and back on and click "ok" in the prompt
8. Click on the stop button, aka "Stop Service Procedure" button
9. Click on "PCM Module initialization/relearn vehicle data"
10. Turn ignition off when prompted, click "ok"
11. Turn ignition on but don't start the vehicle when prompted, click "ok"
12. Click on "TCM Module initialization/relearn vehicle data"
13. Turn ignition off when prompted, click "ok"
14. Turn ignition on but don't start the vehicle when prompted, click "ok"

I get the same error code using this method.

Any ideas?

Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Fri Mar 19, 2021 1:07 pm
by lenko
The second method you are using puts the exact same code in that line as the first method. My question is - has the speedometer been corrected? If it has and everything works ok you've likely accomplished what you wanted. I think I have the same error code in my PCM, but this only shows in Forscan and nothing on the IPC. Everything works good, my speedometer is accurate now and I'm not concerned with the DTC.

Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Sat Mar 20, 2021 2:15 am
by Fresh_1
So after trying unsuccessfully on two different days, I decided to try again today. I didn't do anything different, but apparently the Sun was finally at the correct angle to the Earth, because today it took every size I put in with no error codes. I started smaller, and ended up with the exact size I tried to enter about a dozen times before and it finally worked perfectly. For anyone having issues, my advice would be to wait a couple days and try again.

Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Wed Mar 24, 2021 4:18 pm
by traske
I wanted to advise that I was able to calibrate my speedometer by simply going to the Body Command Module and using the filter and type in "tire". It will bring up a option to change the tire circumference. All you have to do is figure out your new tire circumference in millimeters. Enter it and write in in the program. You can dial in your speed by simply reducing the millimeter number until u are close. And finally when that is finished you run the PCM and TCM relearn programs and then finally delete any DTC codes which there shouldnt be after the PCM and TCM relearn processes. I put 35/12.5/R17 on my 2021 Ford F350 dually and my speedo reads within .1 of actual reading and verified with a GPS app. No DTCs and running perfectly. Hope this helps. It is not necessary to change any As Built codes. When you connect to your truck, you will see the 2 options for BCM As Built and BCM config under the programming function of forscan. Dont use the As Built option, use the BCM config option and filter using tire in the filter bar.

Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Wed Mar 24, 2021 8:39 pm
by rbentnail
Fresh_1 wrote:
Sat Mar 20, 2021 2:15 am
So after trying unsuccessfully on two different days, I decided to try again today. I didn't do anything different, but apparently the Sun was finally at the correct angle to the Earth, because today it took every size I put in with no error codes. I started smaller, and ended up with the exact size I tried to enter about a dozen times before and it finally worked perfectly. For anyone having issues, my advice would be to wait a couple days and try again.
:lol: :lol:
Congrats! That's the way I felt about it when it finally worked for me.

Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Thu Apr 08, 2021 2:15 pm
by Hill208
I currently running 285/65 R20 wheels and was wondering what the code to re-calibrate The speedometer

Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Thu Apr 08, 2021 8:41 pm
by lenko
Hill208 wrote:
Thu Apr 08, 2021 2:15 pm
I currently running 285/65 R20 wheels and was wondering what the code to re-calibrate The speedometer
https://docs.google.com/spreadsheets/d/ ... 2133040050

https://www.binaryhexconverter.com/deci ... -converter

https://docs.google.com/spreadsheets/u/ ... 0/htmlview#

You can enter code, or you can enter tire circumference or you can get code from spreadsheet.

Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Fri Apr 09, 2021 4:36 pm
by JraySD
I changed my speedo yesterday for a 285/60/20 Toyo AT3 on my 2018 F150 2.7l. I tested it and it was very close. Speedo showed 70mph. GPS showed 70.1mph
I then drove to work this morning and my speedometer was off. At 60mph I was going 72mph. How did it revert back to being off? Please advise.

Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Mon Apr 26, 2021 10:00 am
by miller0978
What field can be adjust for focus MK4 model by forsacn software ?
/* I can't found 726-12-01 and 726-15-01 field on the focus MK4 model.

Re: Setting arbitrary tire sizes for speedometer calibration

Posted: Thu May 20, 2021 12:27 pm
by TX_Jax
Using v2.3.40 -- clicking on the item gives you a drop down menu.

However, choosing in the drop down does not work. I assume the choosing of the item would send the proper parameters to the GEM, but it is not.
Writing to GEM 1 Notation 2021-05-19 143849.jpg
Writing to GEM 1 Notation 2021-05-19 143849.jpg (79 KiB) Viewed 672 times