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.
I tried a few things and found that the PCM service procedure worked reliably. The PCM relearn will probably be fixed in ForScan eventually.
That’s strange. I started at 2698 for 285/75R17 and found the sweet spot to be 2580.
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.
thank you very much for this, playing with FORSCAN i found this underUse 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.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.
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.
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.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.
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
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".
So interesting to me that the larger tire is suggesting lower PSI. I’ve already been running them around 36-37 due to comfort. Even after reading the disclaimer - it should make sense - but, my brain doesn’t comprehend.
Your situation is even weirder than mine as both your tires are LT, my stock OBX tire was a regular metric so because I changed to an LT tire it kind of “made sense” to me that I needed the same tire pressure as LT tires (and especially my E rated Ridge Grapplers) have higher load ratings so 35 would be enough. But your case got me wonder because your previous tire is an LT too.So interesting to me that the larger tire is suggesting lower PSI. I’ve already been running them around 36-37 due to comfort. Even after reading the disclaimer - it should make sense - but, my brain doesn’t comprehend.
I should do the chalk test.
Is there any difference in changing the TPMS value? The warning doesn’t go off until it’s in the high 20s.
