GM Terms

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.

Look for the smooth Chevy logo on the grill, which is transparent to radar. Car dealers will often reuse external photos, so don't trust them. The left panel of the steering wheel will have a central button to adjust follow distance.

Volt ASCM is the trunk, on the driver side, behind the storage cabinet:

Unofficial Vehicles

Any GM vehicle 2016+ with front camera and lane keeping. These will only control steering, not gas/brake. With a comma pedal, limited longitudinal control is possible by using Low gear to decelerate. To upstream these vehicles, find a CAN bus and command to control friction brakes!

For the Chevy Bolt, 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

Other ASCM Harness Methods

Bypass ASCM and power the radar, choose one of:
1. GM Giraffe - $300-$500
2. ASCM connector Amazon / Amazon alt - $7-10 + Cam molex connector digikey - $10
3. 0.1" header homebrew harness

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