GM - commaai/openpilot Wiki

Original URL: https://github.com/commaai/openpilot/wiki/GM

Chevy

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GM Terms

Also see general terms.

Term Abbreviation Definition
Advanced Safety Control Module ASCM Car computer/module that does sensor fusion from Radar and Camera to create ACC and LKA messages to PCM (powertrain control module). Typically located in the trunk.
Calibration n/a Packaged adjustments to running parameters of firmware running on GM vehicles. Updates available from SPS within TIS2Web
Firmware n/a Base operating system for various devices throughout the vehicle. Updates available from SPS within TIS2Web
GDS2 Global Diagnostic System 2 GM system for advanced diagnostics and firmware flashing
GMLAN GM Local Area Network Single wire propriety interface present on the CAN connector in GM vehicles.
MDI Multiple Diagnostic Interface GM service device connecting the vehicle to a computer. Lower price generics exist such as vxdiag.
SPS Service Programming System Firmware and calibrations within the TIS2Web application. Updates can be seen for vehicles by VIN without cost here.
Tech2Win Tech2 for Windows Emulated legacy diagnostic interfaces for Windows. Runs in an emulated terminal.
TIS2Web Techline Information System ACDelco site providing diagnostics and firmware for cars on a subscription basis. Interacts with vehicle via GM MDI. Java webstart application.

Vehicle Requirements

The GM RPO code for CRUISE CONTROL AUTOMATIC, ADAPTIVE WITH STOP/GO is KSG. Most GM 2016-2020 vehicles with ACC, LKA can be supported.

Radar is behind flat Chevy logo:

ASCM in the trunk:

Unofficial Vehicles

Any GM vehicle 2016+ with front camera and LKA. These will only have ALC, not ACC. With a comma pedal, limited ACC is possible using Low gear. Find a way to control friction brakes!

For the Chevy Bolt specifically, see the openpilot Bolt wiki.

Capabilities

First engage must be above 18 mph.

Minimum Speeds

All: Below 8 mph, LKA steering is unavailable.

2017: 18 mph longitudinal control, although 0 mph often works, but sometimes cruise faults.

2018+: 0 mph longitudinal control

Auto-Resume

2017: Auto-resumes from stop at 0mph.

2018+: Must press RESUME to resume from stop.

Hardware

Recommended

  1. comma two devkit w/ OBD-II car harness
  2. ASCM wiring harness

Other ASCM Harness Methods

Harness Examples

ASCM 14-pin stub

Camera stub

Connect switched +12V (e.g. ignition on, rearview mirror connector or driver fusebox) to pin 9 (radar power) of cam connector. This will turn on the front radar when the car is powered on.

Original instructions from Zoneos

Homebuilt OBD-II to OBD-C Harness

Map OBD-II to OBD-C female (at comma two) schematic

This requires the panda intercept relays panda to be disabled:

OBD-II OBD-C
4 GND GND
6 CAN1H A2 CAN0H
14 CAN1L A3 CAN0L
3 CAN2H A11 CAN1H
11 CAN2L A10 CAN1L
12 CAN3H B2 CAN2H
13 CAN3L B3 CAN2L
16 12V VBUS
B8 SBU2 1kΩ to GND