In the world of On-Board Diagnostics (OBD-II), standard "Mode 01" provides basic emissions-related data common to all cars (like RPM or coolant temp). However, (also known as Service 22 or Enhanced Diagnostics) is a proprietary protocol used by manufacturers like GM and Ford to transmit "enhanced" data. This includes:
The is more than a cable. It is a philosophy: that the manufacturer’s proprietary data belongs to the owner of the car. By building or buying a Mode 22 scanner, you are keeping the OBD1 era alive, fixing your own vehicle, and tuning with precision that dealerships in the 1990s couldn’t even offer. gm mode 22 scan tool by terry
Terry created a series of definition files (ADX/ADS) and a hardware schematic that allowed a standard laptop serial port to talk to the GM ECU using Mode 22 commands. His breakthrough was mapping the memory addresses for: In the world of On-Board Diagnostics (OBD-II), standard