Gm Mode 22 Scan Tool By Terry ~repack~

A special cable that converts the 12-pin ALDL connector (usually found under the dashboard) to a serial port connector (RS-232). Connection Guide:

To understand why Terry's scan tool was so innovative, it is necessary to look at how On-Board Diagnostics (OBD-II) function. Standard OBD-II utilizes several public "Modes" specified by the Society of Automotive Engineers (SAE):

For users with newer GM models (2010+), modern tools often provide more comprehensive "dealer-level" capabilities:

Unlike generic scanners, Terry’s tool is designed to interpret the complex data streams returned by GM ECUs when requested via Mode 22. gm mode 22 scan tool by terry

For those seeking to access GM Mode 22 data today, several modern alternatives offer a more polished experience:

Using the GM Mode 22 tool requires a bit more technical comfort than plugging in a retail code reader.

Bottom line

Interfacing directly with manufacturer-specific modes carries minor risks if done incorrectly. Follow these rules to protect your vehicle's electronics:

Terry’s Mode $22 tool usually operates via common hobbyist interfaces:

Mode $22 allows a scan tool to request specific data parameters (PIDs) directly from individual electronic control modules (ECUs). This includes data from the: Powertrain Control Module (PCM) Transmission Control Module (TCM) Body Control Module (BCM) Electronic Brake Control Module (EBCM/ABS) A special cable that converts the 12-pin ALDL

Plug your compatible OBD2 adapter (such as an OBDLink MX+) into your GM vehicle's diagnostic port located under the driver-side dash.

Unlike a $50 Amazon scanner, Terry’s tool is not just a code reader. It is a full-blown diagnostic suite. Here is what you get:

: Allows isolating a bad spark plug or coil pack before a check engine light blinks. For those seeking to access GM Mode 22

is different. It is a proprietary, manufacturer-specific mode defined by the SAE J2190 standard and used primarily by General Motors and Ford. This "enhanced mode" allows access to a much wider array of data, known as extended PIDs . These GM-specific parameters include:

While many cheap ELM327 clones fail to process complex Mode 22 custom initialization strings, high-quality or genuine ELM327 interfaces can be configured via AT commands to send raw hex to GM modules.