BCM tune for speed limiter removal on GMC trucks

American Delco GM ECUs and PCMs, ALDL, OBD 1.5.
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hidalga
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BCM tune for speed limiter removal on GMC trucks

Post by hidalga »

Is there any way to tune a BCM from the latest versions of GMC trucks to free the speed limiter? If so, any idea how I could start?
gmtech825
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Re: BCM tune for speed limiter removal on GMC trucks

Post by gmtech825 »

latest version as in 2023 MY?
hidalga
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Re: BCM tune for speed limiter removal on GMC trucks

Post by hidalga »

Yes, any 2019+ GM BCM, I'm aware that there's a way to read the bin file, but I don't know if there's a checksum, seed/key algo, where should I look at so I can free the speed limiter
gmtech825
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Re: BCM tune for speed limiter removal on GMC trucks

Post by gmtech825 »

seed/key algo is 5 byte 0x24. checksums are the first two bytes of the segment calculated by 16 bit big endian NOT of the whole segement excluding the first two bytes.

this only applies to the non global B vehicles I've looked at.
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Gatecrasher
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Re: BCM tune for speed limiter removal on GMC trucks

Post by Gatecrasher »

19-21 are Global A. I don't think the BCM in those has anything to do with speed limiters?
22+ are Global B / VIP, and effectively untouchable.
ironduke
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Re: BCM tune for speed limiter removal on GMC trucks

Post by ironduke »

hidalga wrote:Yes, any 2019+ GM BCM, I'm aware that there's a way to read the bin file, but I don't know if there's a checksum, seed/key algo, where should I look at so I can free the speed limiter
Mind sharing where you saw that the bin file can be read?? I'd be interested in something like that..
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Tazzi
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Re: BCM tune for speed limiter removal on GMC trucks

Post by Tazzi »

ironduke wrote:
hidalga wrote:Yes, any 2019+ GM BCM, I'm aware that there's a way to read the bin file, but I don't know if there's a checksum, seed/key algo, where should I look at so I can free the speed limiter
Mind sharing where you saw that the bin file can be read?? I'd be interested in something like that..
Immo related tools will read and write them since they are designed to clone the BCms to copy security/key data to other BCMs :thumbup:
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ironduke
Posts: 576
Joined: Thu Feb 13, 2020 11:32 pm
cars: Mainly GM trucks, a Cruze and an Equinox for dailys..

Re: BCM tune for speed limiter removal on GMC trucks

Post by ironduke »

Tazzi wrote:
ironduke wrote:
hidalga wrote:Yes, any 2019+ GM BCM, I'm aware that there's a way to read the bin file, but I don't know if there's a checksum, seed/key algo, where should I look at so I can free the speed limiter
Mind sharing where you saw that the bin file can be read?? I'd be interested in something like that..
Immo related tools will read and write them since they are designed to clone the BCms to copy security/key data to other BCMs :thumbup:
Thanks, I think I was a little too excited and assumed he meant something open source or at least somewhat inexpensive.. lol.. I have no need for this, just would like to see it for myself, lol..
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