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Discussion Starter #1
Hi all,

Got my new Bolt yesterday, and as so many of you are really disappointed at GM lack of technical improvment over the years.

I was inspired by @Pigwich in OK Google, Start the RED CAR!

My plan would be to ditch completly the OnStar stuff and implement via OBD2 a LTE IOT that could report all the needed data in real time, and also precondition the car remotely.

A few use cases:
  • get battery usage data and efficacy based in temperature, and speed.
  • look, unlook and remote start the car.
  • get live battery status and charge ( instead of 30 seconds OnStar refresh delay)
  • connect everything with Google Assistant
  • display car status on Google Nest Hub ( battery charge and range )


Does anybody know what data is available from OBD2 or other data port ? Is data still going through even if the car is powered off ?

I'll keep updating this post with my findings

I am also looking for other developers to join me on a GPL open source GitHub project.
 

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Hi all,

Got my new Bolt yesterday, and as so many of you are really disappointed at GM lack of technical improvment over the years.

I was inspired by @Pigwich in OK Google, Start the RED CAR!

My plan would be to ditch completly the OnStar stuff and implement via OBD2 a LTE IOT that could report all the needed data in real time, and also precondition the car remotely.

A few use cases:
  • get battery usage data and efficacy based in temperature, and speed.
  • look, unlook and remote start the car.
  • get live battery status and charge ( instead of 30 seconds OnStar refresh delay)
  • connect everything with Google Assistant
  • display car status on Google Nest Hub ( battery charge and range )


Does anybody know what data is available from OBD2 or other data port ? Is data still going through even if the car is powered off ?

I'll keep updating this post with my findings

I am also looking for other developers to join me on a GPL open source GitHub project.
There are a whole mess of CAN busses in the car. And none of the really juicy stuff is available on the one by the hood release except the standard fare OBD2, which is still plenty useful. I don't think it stays on long after the car is shut down however. Try a Pi zero with a GSM radio and a CAN hat. There's some company out there peddling vaporware of just such a device. There's a huge Google sheets spreadsheet out there somewhere with all of the PIDs (register locations as we say in the industrial world) and how to format them into useful data.
 

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Discussion Starter #3
Ok, great to know! I was mentioning OBD2 because it's an easy access, but I am also fine connecting directly to a CAN bus too, even if its mean we have to splice some connectors :)

Do you know if there is any docs/ICD that exists on what data bus carry which data ?
 

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I've mentioned in this forum before, but such a product already exists in Korea by a 3rd party precisely because GM does not provide OnStar service in the country. And it apparently does hook onto the OBD-II port, although it might tap into other ports as well. Obviously, the maker isn't disclosing the details but at least I can tell you that it's completely doable. Stuff like monitoring traction battery and remote lock/unlock are all available over LTE using their own smartphone app. There'a a photo of the module about halfway through this page:

 

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I personally have a Macchina P1. The AutoPi doesn't mention anything beyond a single CAN interface and no SWCAN/LS-CAN - P1 has two standard CAN interfaces, one SWCAN/LS-CAN, and a few other I/O interfaces, and it's cheaper. Neither the BCM in the AutoPi nor the OSD3358 have very good deep sleep modes for this application though.

Remote wakeup is not possible on 2020 Bolts without splicing into the harnesses near the radio, and may not be possible on 2017-2019 because the OBD connector, while not wired to the SDGM for all communications, is still on the wrong side of the SDGM.
 

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Can you give in introduction in how to use and setup P1?
Unlock, remote heat,...possible?
As I mention in my post - a lot of things are only possible if you splice into wiring harnesses near the radio, which I have not gotten to yet.

Basically anything that interfaces at the diagnostic connector is a definitive no-go for anything beyond basic logging on a 2020, and probably also on 2017-2019.

From the main diagnostic connector, I can:
Cause car electronics to "wake up" and start talking on the buses (but not do anything useful)
Make the windows go up and down IF the car is OFF. Volts apparently did not block this diagnostic interface when on, but Bolts do.

Once I figure out a good/safe way to splice into the radio harness (I'm having trouble finding the appropriate connector - the service manual's connector designations are a bit weird and translate, unfortunately, to a TE part number not sold to anyone but GM - but I've seen people selling GM passthrough harnesses for the radio so the connectors have to be available SOMEWHERE, I just haven't yet figured out where.)

Edit: Whoops, radio connectors are Molex, maybe I was looking at SDGM connectors - but endusers can't easily buy them:

The description says it's MX64 series, but Molex's MX64 series looks like a different connector type...

Edit: Might have been replaced by Molex 34729-0201? Looks like while the part lookup says MX64, the STAC64 connectors look to be the closest match.
 
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