[ManBro]

Try 2190mm

I messed with this some tonight on my 2020 awd. I tried a bunch of circumferences and finally settled on 2190mm up from 2164. The next size up I tried is 2199mm and that threw the U0422 pcm dtc. So the max seems to be somewhere between 2190mm and 2198mm.

Immediately after writing the new circumference do the PCM relearn. Then do the AWD relearn. Finally, clear any DTCs.

 

[ArgonautVans]

Try 2190mm

I messed with this some tonight on my 2020 awd. I tried a bunch of circumferences and finally settled on 2190mm up from 2164. The next size up I tried is 2199mm and that threw the U0422 pcm dtc. So the max seems to be somewhere between 2190mm and 2198mm.

Immediately after writing the new circumference do the PCM relearn. Then do the AWD relearn. Finally, clear any DTCs.

it’s interesting because 2164mm translates to 27.12” diameter. And 2190mm translates to 27.44”. Should Help the speedo 1% or so

Both are less than the actual diameter of 28” for 235/65r16, which is odd.

my 2020 speedometer is maybe 2-3% faster than my actual speed from the factory? So with 245/75r16 my speed was only around 6% faster.

 

[jmn]

it’s interesting because 2164mm translates to 27.12” diameter. And 2190mm translates to 27.44”. Should Help the speedo 1% or so

Both are less than the actual diameter of 28” for 235/65r16, which is odd.

my 2020 speedometer is maybe 2-3% faster than my actual speed from the factory? So with 245/75r16 my speed was only around 6% faster.

That circumference calculation bothered me too. After some research I found you need to multiply the calculated circumference by a squash factor of around 0.967. That 28”*0.967 gives you the factory 2162 setting for 235/65R16. That would put the 245/75R16 at 2351 well outside the 2190 maximum. My assumptions is that 2190 is to deal with minor adjustments for the factory 235/65R16s tires.

 

[6ixgun]

^^^ I drive about 5,000 miles a month in my van, so 5,000+10% = 5,500. Over the life of my van (probably 150,000 miles), that's a difference of 15,000 miles. The van's computer would think it traveled 150,000 miles, but it actually covered 165,000 with the oversized tires.

Sounds like a bonus to me - not a problem...

 

[LEVLHED]

I am currently trying to get my '22 re-calibrated for the 245/70 R17's I just added. I had no idea it would be so difficult/impossible! Wondering if anyone has ever solved this? All I've been able to do so far is set the circumference to the max hard limit.

I currently have the van at a dealer for a recall job, who thinks they can do it- but I'm not hopeful given what I know and everything I've read here. Will find out tomorrow.

 

[MgA_ODEN]

Good luck.

 

[6ixgun]

We have looked into extensive ECM programming , I've explored nearly every ForScan parameter and was never able to get the speedo to indicate correctly. Anything I adjusted also effected shift points or caused the ECM to throw errors. The Ford Transit speedometer sensor is intensely simple - nothing more than a magnetic hall sensor on the rear wheel - it is actually very easy to intercept the pulses that are coming from that sensor and change their frequency. I am an engineer by trade but do not have the time to design the circuit to do it but I cannot imagine it would take much.

After it was all said and done, I decided to simply make the mental correction on mileage, speed and fuel range.

There was a company that provided the exact solution in a more elegant package for Marxist nanny state Europeans who had to have "speed validation checks" done on their cars just to get the tags - but it appears they are no longer making it, its been out of stock for a long time.... it could be adjustable on the fly to add 5% or 10% correction.

FORD TRANSIT (7th GEN.) Speedometer Calibration Device | Super Kilometer Filter | Mileage Blocker

FORD TRANSIT (7th GEN.) speedometer calibration will ensure that the speedometer displays the correct speed after installing larger tires or rims.

superkilometerfilter.com

 

[LEVLHED]

We have looked into extensive ECM programming , I've explored nearly every ForScan parameter and was never able to get the speedo to indicate correctly. Anything I adjusted also effected shift points or caused the ECM to throw errors. The Ford Transit speedometer sensor is intensely simple - nothing more than a magnetic hall sensor on the rear wheel - it is actually very easy to intercept the pulses that are coming from that sensor and change their frequency. I am an engineer by trade but do not have the time to design the circuit to do it but I cannot imagine it would take much.

After it was all said and done, I decided to simply make the mental correction on mileage, speed and fuel range.

There was a company that provided the exact solution in a more elegant package for Marxist nanny state Europeans who had to have "speed validation checks" done on their cars just to get the tags - but it appears they are no longer making it, its been out of stock for a long time.... it could be adjustable on the fly to add 5% or 10% correction.

FORD TRANSIT (7th GEN.) Speedometer Calibration Device | Super Kilometer Filter | Mileage Blocker

FORD TRANSIT (7th GEN.) speedometer calibration will ensure that the speedometer displays the correct speed after installing larger tires or rims.

superkilometerfilter.com

wow. that is exactly what the Dr. ordered

 

[LEVLHED]

wow. that is exactly what the Dr. ordered

yeah, it isn't just the Transit out of stock - it is all of the calibrator/filters. I have messaged them to see if there's any chance of seeing them available again (I think I got past their stupid AI bot)

Got excited when I saw the blocker in stock, but that literally stops the odometer which is not helpful.

 

[LEVLHED]

No surprise around these parts that the dealer said they couldn't re-calibrate then.

 

[LEVLHED]

yeah, it isn't just the Transit out of stock - it is all of the calibrator/filters. I have messaged them to see if there's any chance of seeing them available again (I think I got past their stupid AI bot)

Got excited when I saw the blocker in stock, but that literally stops the odometer which is not helpful.

hopeful but vague reply from SKF regarding the speedo filter:
"New device for that model will be out for sale later this year"

 

[johnny_honda_]

No surprise around these parts that the dealer said they couldn't re-calibrate then.

Yeah I'm not surprised either. This was literally not even done on their now deprecated 'Transit Trail' Package, when I learned that even the Transit Trail had wrong speedometers that told me everything I needed to know.

 

[ArgonautVans]

Cross posting this from another thread. Forum member @CincyBearcats was smart and tracked her as-built data for her trail before and after having the tire size on her van programmed back DOWN from 245/75r16 to 235/75r16.

values on the left side theoretically are for 245/75r16 (30.5”). At some point I may try to dig in to my as-built data and see if my values on my 2020 match the right side (small tires). If they do, I may try changing them to match the left!

Would be curious to see what the as-built data looks like for other 2020+ vans too

this could be the key to finally unlocking
updated tire sizes and accurate speedometers on 2020+ AWD vans!

We received our Transit Trail prior to the tire rub recall, so it still has the 245/75R16 tires. We recently took it to the dealership to get the steering bolt recall and the EPAS ground cable recall addressed. While there, I had hoped to get the tire rub recall addressed by leaving the large tires (245/75R16) on the Transit Trail rims and putting the tiny tires (235/65R16) on a set of steel wheels that I had acquired on the forum and brought with me. The dealership refused to do so because Ford requires the original tires to be returned. Apparently this is a federal mandate with recalled parts. Therefore, I opted to not have the tire rub recall addressed so that I could keep the larger tires. My plan is to have the recall addressed once the tires are used up.

In the meantime, I was hoping to at least get the software updates for the tire rub recall. I realized that the speed governor would not be removed, but the tire size offset would at least let me go slightly faster, which is a big deal in NM where the speed limits are 75 mph and the average traffic goes 80 mph. By this point my relationship with the service advisor had severely deteriorated (long story). Therefore, when I went to pick up the vehicle, I circumvented the service advisor and took a 6-pack directly to the technician. I asked that he at least run the software updates associated with the tire rub recall despite not being able to clear the recall from the vehicle in general. He obliged and ran a few updates to a few modules.

Because I had backed up the factory as built data, I was able to track the differences made. In case anyone is interested, the only changes were made to the following modules:

• ABS - block 4
• APIM - block 7
• BCMii - blocks 15, 51, 52

All other modules were unchanged.

Here are the specific changes that were made (original on left, updated on right):

ABS
;Block 4 ;Block 4
760G4G1FE240908009F | 760G4G1FE21660800F9

APIM
;Block 7 ;Block 7
7D0G7G125003B00003F 7D0G7G125003B00003F
7D0G7G2E290AFC800C9 7D0G7G2E290AFC800C9
7D0G7G30056568F001C | 7D0G7G3005656750002
7D0G7G4A88A 7D0G7G4A88A

BCMii
;Block 15 ;Block 15
726GFG1C10401750987 | 726GFG1C10401750886
726GFG2303047EB | 726GFG275304730
;Block 51 ;Block 51
726J3G17A6076ADC945 | 726J3G13F2533E88C8A
726J3G2AE77D16DEDD0 | 726J3G2EB329428A801
726J3G325F8F305EA80 | 726J3G360BDB640AF43
726J3G482882E79B2E5 | 726J3G4C7CD6B3CF7B4
726J3G50094122851 | 726J3G545D1576D5D
;Block 52 ;Block 52
726J4G1000000000080 | 726J4G1D13708315516
726J4G2000000000081 | 726J4G234083E313C68
726J4G3000000000082 | 726J4G375FFFDEFF0D2
726J4G4000000000083 | 726J4G46BF073DF0939
726J4G50000000084 | 726J4G52C53CE6233

 

[LEVLHED]

I thought the speedometers were off on the Trail too though?
my 245/70R17's are 30.5" - I'm tempted to dig in and try this

 

[johnny_honda_]

I'm pretty sure the speedo was off on all trails as well. I don't have one to confirm, but I've read that a. few places.

 

[Dave01]

Might look at an online tire size comparison tool. The one I usually use gives me all the size differences, as well as MPH differences between the two tire size inputted.

 

[ArgonautVans]

I'm pretty sure the speedo was off on all trails as well. I don't have one to confirm, but I've read that a. few places.

Some of the trails were a few mph slow, some a few mph fast, and some spot on I believe

@CincyBearcats how did your speedometer read before and now after the software update?

 

[Dave01]

Here's another FYI for you. Every speedometer that comes from a US factory, for it's original configuration, reads a bit faster than actual road speed to protect the manufacturer from frivolous accident lawsuits. Usually around 2mph, but sometimes as much as 4. Only time a trail would read slower than the actual road speed was from a modification in drive train and / or tire size.

 

[ArgonautVans]

Here's another FYI for you. Every speedometer that comes from a US factory, for it's original configuration, reads a bit faster than actual road speed to protect the manufacturer from frivolous accident lawsuits. Usually around 2mph, but sometimes as much as 4. Only time a trail would read slower than the actual road speed was from a modification in drive train and / or tire size.

your fyi is nice, but multiple people experienced their trail speedometers reading slow from the factory.

not sure if you’ve paid attention to the trail saga but they didn’t exactly execute it very well so it’s not surprising the speedometer calibration was bungled for some vans too

 

[Dave01]

Yeah, I'm old enough to remember having to calibrate squad car speedometers in the age before radar. Had a tray of different gears, and even then they were never truly accurate. Get it close, swap tire sizes to get it as close as you could, then put the 'calibrated' decal on the speedometer.

Now we just go in and play with the tire size and let the computer handle it. All because of aggressive lawyers. And that's before some tech fat fingers an entry, or inputs the wrong vehicle info.