Gm Mode 22 Scan Tool By Terry Jun 2026

: Capable of reading and clearing diagnostic trouble codes (DTCs) to help identify and reset check engine lights.

based USB interfaces. It is widely listed as part of free software bundles provided with affordable OBD-II scanners. Quadstar Tuning LLC Historical Context OBD-II free software - OBDTester

It was designed specifically to interface with General Motors vehicles (primarily those using the ALDL or early CAN bus systems) to request data using . Unlike standard tools that focus on Mode $01 (live data) or Mode $03 (trouble codes), this tool allows users to dive deeper into the vehicle's computer systems. Key Features of Terry's Scan Tool:

These are the preferred hardware choices. Devices from OBDLink support advanced ST command sets, massive data buffers, and the high-speed transfer rates required to handle packed Mode 22 responses without dropping frames. gm mode 22 scan tool by terry

: Unlike generic OBD-II modes (like Mode 01), which only provide legally mandated emissions data, Mode 22 allows the user to request manufacturer-specific Parameter IDs (PIDs) Live Sensor Monitoring : It can display real-time data such as Engine RPM Coolant Temperature Vehicle Speed Fuel System Status Compatibility : The software is specifically designed to work with

A high-quality OBD-II adapter is required. High-speed USB interfaces or Bluetooth adapters using the STN1110 or ELM327 (v1.3a or higher) chipsets work best. Cheaper, counterfeit clones often drop data packets during Mode 22 requests.

Mode 22 is an enhanced diagnostic request protocol reserved for GM and Ford vehicles. Instead of broad, generic information, Mode 22 asks the vehicle's computer for custom Parameter IDs (PIDs) mapped directly to its internal RAM. : Capable of reading and clearing diagnostic trouble

Always ensure your vehicle battery is fully charged or connected to a maintainer. Voltage drops during deep diagnostic polling can cause modules to drop offline.

: Works with standard ELM327 OBD-II interfaces , including USB and Bluetooth variants.

While Terry's tool was revolutionary at the time, diagnostic technology has moved forward. If you cannot find a working copy of this software, or if you have a newer vehicle, consider these alternatives: Quadstar Tuning LLC Historical Context OBD-II free software

Requests standardized data points like engine RPM, vehicle speed, and coolant temperature. The update rate is often slow.

The GM Mode 22 scan tool by Terry is a powerful diagnostic tool designed for GM vehicles. Its features, such as bi-directional control, real-time data streaming, and customizable interface, make it an essential tool for technicians. The tool's benefits, including improved diagnostic efficiency, enhanced accuracy, and increased productivity, make it a valuable asset for independent repair shops, dealerships, and fleet maintenance operations.

A developer and enthusiast named Terry created a custom PC-based software script and interface mapping. It targeted the exact memory addresses and Mode 22 PIDs (Parameter IDs) used by GM vehicles. Often distributed as a lightweight executable, an Excel-based macro tool, or an open-source script, the tool allowed users to pair a basic hardware interface with a laptop to extract professional-grade data. Key Features and Capabilities