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16Kobra
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the auto up would be awesome function, especially loading car in enclosed trailer. Getting my fat a$$ out of car with window up really sucks.
bendensez
Well-Known Member
Hey all. As many of you may be finding out, memory mapping has changed significantly for MY2020. For those wanting to calibrate their speedometers for new wheel circumferences, such as when moving to 30 series from 35 series on a non-R, the wheel circumference is no longer stored at 726-12-01: xxxx ???? xxyy. It is obvious that the two bytes for wheel circumference no longer reside there by inspection of current as-built data for my car and some other 2020s. Based on some 2019 model year as-built data and corroboration from multiple posts on this forum, I'm looking for 0844 hex for wheel circumference on my non-R 350. The GT350R should have 07F9 hex for wheel circumference. (FWIW, It looks like Ford factors in a ~3% circumference reduction from calculated due to tire compression under weight) Comparing 2020 as-built data from my car and a 2020 GT350R, the entries for 726-12-01 are identical between the two and a number much, much larger than my wheel circumference in mm. After sleuthing around on other forums, I found mention on the F250 forum that the two bytes for wheel circumference (for 2020) are now split between 726-15-01: xxxx xxxx ??yy and 726-15-02 ??xx xxxx xxyy. I wondered if the same might apply to the GT350. So, back to as-built data for my 2020 GT350 and a 2020 GT350R and I find the expected wheel circumferences 0844 and 07F9, respectively, split between those memory locations.
It appears the the 2020 GT500 and 2020 GT500 share the same modules and software versions and also the new memory mapping. To further corroborate the wheel circumference location, I looked at as-built data for a 2020 base GT500 and it has 0854 hex split between those two positions. 0854 hex is 2132 decimal. The calculated wheel circumference of the 315/30R20 tire is 2190 mm. 2132 is 97.4% of 2190, so there is the ~3% factor for reduction in circumference.
So, I do believe 726-15-01: xxxx xxxx ??yy and 726-15-02 ??xx xxxx xxyy hold the two bytes for wheel circumference used for speedo cal on both the GT350 and GT500. Don't forget to perform the re-learn on the PCM after this change. I will be trying this once I get my new wheels on and report back.
It appears the the 2020 GT500 and 2020 GT500 share the same modules and software versions and also the new memory mapping. To further corroborate the wheel circumference location, I looked at as-built data for a 2020 base GT500 and it has 0854 hex split between those two positions. 0854 hex is 2132 decimal. The calculated wheel circumference of the 315/30R20 tire is 2190 mm. 2132 is 97.4% of 2190, so there is the ~3% factor for reduction in circumference.
So, I do believe 726-15-01: xxxx xxxx ??yy and 726-15-02 ??xx xxxx xxyy hold the two bytes for wheel circumference used for speedo cal on both the GT350 and GT500. Don't forget to perform the re-learn on the PCM after this change. I will be trying this once I get my new wheels on and report back.
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madweazl
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Looking at my .ab file, there are 5 entries for the ACM; is the one above the only one responsible for the engine noise or is it coming from other channels (and/or memory locations) as well (saw some reference to this in a previous post in this thread but it didnt look like there was any confirmation)?
Caballus
Well-Known Member
Yeah, I think @JZTRK and @Spart cracked the code. Part of my initial concern, in addition to making sure the tweeters were not disabled, was distinguishing between ESE and ANC on the 2019. We had a discussion about it a while back and discovered that the GT350s at that time only had ESE. 2019+ seem to have both.
https://www.mustang6g.com/forums/th...ed-through-speakers.52476/page-2#post-1253331
https://www.mustang6g.com/forums/th...ed-through-speakers.52476/page-2#post-1253331
bendensez
Well-Known Member
I installed my R-spec Signature SV902 last week on my 2020 GT350 (couldn't be happier
). I stayed with 19" wheels, but changed to 30 series MPS4S from the stock 35 series MPSC2. I stuck with 295 front and 305 rear widths as the MPS4S 295/30 and 305/30 are perfectly matched to the R-spec 11" and 11.5" wheel widths. As expected, my speedometer was off (indicated slower than GPS speed) by the ratio of new rear wheel circumference to old rear wheel circumference - right around 4% low.I can verify that the two bytes for wheel circumference are indeed now held at BCM addresses 726-15-01: xxxx xxxx ??yy and 726-15-02: ??xx xxyy for the 2020 GT350. There is no reason to believe, per my previous post, that the same goes for the 2020 GT500.
For reference, the stock GT350 has 0844 HEX split between those positions (305/35R19 circumference in mm * 0.9675). My new wheel circumference * 0.9675 comes out to 2023 mm, which is 07E7 HEX.
I made the following changes to the BCM:
726-15-01: xxxx xxxx 08yy --> xxxx xxxx 07yy
726-15-02: 44xx xxyy --> E7xx xxyy
As expected, I got the P160A - Control Module Vehicle Options Reconfiguration Error DTC after writing the change to the BCM. Also as expected, the PCM re-learn took care of this.
My speedometer is now accurate (verified by GPS).
Hope this helps you guys!
Last edited:
Caballus
Well-Known Member
Do you mean 11" and 11.5"? Non-R is 10.5 & 11.I installed my R-spec Signature SV902 last week on my 2020 GT350 (couldn't be happier
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JAJ
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Interesting change deep inside the BCM - thanks for posting it. I have a 2016 GT350 and I swapped from my winter tires (285/40x19 rears) to my OEM MPSS tires (305/35x19) this week. Fired up Forscan but instead of going into the AS Built screen for the BCM, I went to the regular screen. I was surprised to find a setting for wheel circumference, and it's a single operation - put in the mm measure (I changed from 2160 to 2116 mm) and hit write and you're done. No HEX to enter. Worked great. Still have to fix the PCM DTC, but that's a single entry as well. Very easy.I installed my R-spec Signature SV902 last week on my 2020 GT350 (couldn't be happier
I can verify that the two bytes for wheel circumference are indeed now held at BCM addresses 726-15-01: xxxx xxxx ??yy and 726-15-02: ??xx xxyy for the 2020 GT350. There is no reason to believe, per my previous post, that the same goes for the 2020 GT500.
For reference, the stock GT350 has 0844 HEX split between those positions (305/35R19 circumference in mm * 0.9675). My new wheel circumference * 0.9675 comes out to 2023 mm, which is 07E7 HEX.
I made the following changes to the BCM:
726-15-01: xxxx xxxx 08yy --> xxxx xxxx 07yy
726-15-02: 44xx xxyy --> E7xx xxyy
As expected, I got the P160A - Control Module Vehicle Options Reconfiguration Error DTC after writing the change to the BCM. Also as expected, the PCM re-learn took care of this.
My speedometer is now accurate (verified by GPS).
Hope this helps you guys!
I wonder if this Forscan feature might also be available for the 2020 BCM - any idea?
bendensez
Well-Known Member
I don't think the 2020's have been mapped out thoroughly enough yet. The double honk disable on the 2020 is also in a different location and one of the guys in the GT500 section stated that the simple programming method on his 2020 GT500 modified the old location and therefore didn't do the trick... The 2020 GT500 and 2020 GT350 share the same BCM PN and software versions...
bendensez
Well-Known Member
They are different. When I working on this, I compared some 2019 as-built configurations to my 2020 and found the wheel circumference value at the "old" 726-12-01 location for 2019.
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