Normal install for GM ASCM cars

[adeebshihadeh]

Can we make the ASCM GM cars a completely normal install? That means a single harness, and we remove the OBD-II harness and the 3rd party L&P harness.

I haven't looked into this at all yet, so not sure it's possible. If it's not, let's close this.

It's fine to lose functionality, such as longitudinal control. A normal install will get the ASCM cars back on https://comma.ai/vehicles.

In order to claim the bounty:

• post the harness diagram
• must work for the currently supported Chevy Volts
• get a PR merged to move the GM ASCM cars to this new harness

[Thinkpad4by3]

I have a working port of this running. Harness uses standard car-harness box at the ASCM with a cable running to the front (similar to Nissan Rogue installation). Latest master is running, confirmed working with stock ACC long, resume, set speed, gas override, etc. I will follow up with diagram, route and PR tomorrow. Car is a 2018 Chevy Volt Premier w/ ACC.

[Thinkpad4by3]

Here's what I came up with:

Harness just intercepts the PT bus at the ASCM. Everything else is passed through.

I obtained the connectors here, I am not sure of their actual P/N: https://www.amazon.com/RED-WOLF-Replacement-Connector-Compatible/dp/B099MY1WKR/

Changes were needed in Panda due to quirk with one of the message on GM failing to send after the ASCM boots up.
OpenDBC PR: #1524
Panda PR: commaai/panda#2088

Here is a route of it working on my Volt: 20cb801701fc8237/0000002b--160ea66fef