The true value of Terry's tool was its ability to offer a deep, if sometimes cryptic, look into a GM vehicle's operation, far beyond the reach of a basic code reader. This made it ideal for several diagnostic and tuning tasks.
The GM Mode 22 scan tool, developed by Terry, is a software-based diagnostic tool designed to interface with General Motors vehicles. This review aims to provide an exhaustive analysis of the tool's capabilities, features, and performance.
Transmission diagnostics are usually locked behind premium scan tool paywalls. With this tool, you can monitor: Transmission fluid temperature (TFT) Fluid pressure switch states Shift error times (in milliseconds) Torque converter clutch (TCC) slip speed and duty cycle 4. ABS and BCM Data Retrieval
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: gm mode 22 scan tool by terry
While modern professional scanners like the FOXWELL NT510 Elite offer comprehensive bi-directional controls, this tool serves as a lightweight alternative for specific GM diagnostics:
Depending on the version and hardware adapter used, the tool can command specific vehicle components. Users can test fuel pumps, actuate ABS valves for brake bleeding, or reset learned values like Crankshaft Position Variation (CASE) Learn. Hardware and Software Requirements
Released entirely free of charge, the last known stable version is 1.5, which the developer created to obtain both standard and extended Parameter Identifiers (PIDs) from a vehicle's computer. Despite a modest file size of just 1.49 MB, the software represented a significant leap in accessibility for DIY mechanics. The true value of Terry's tool was its
Do not use “All Data.” Hand-pick:
This indicates an incorrect baud rate setting in the software or device manager. Disconnect, adjust the speed, and retry.
Interfacing directly with manufacturer-specific modes carries minor risks if done incorrectly. Follow these rules to protect your vehicle's electronics: This review aims to provide an exhaustive analysis
: It is frequently bundled with ELM327 USB or Bluetooth diagnostic kits as part of a free software suite.
What (like an OBDLink or ELM327) do you plan to use?
Based on the existing reputation of "Terry" (likely Terry Johnson of ) and his existing software (Terry's GM Scan Tool), the most logical and high-impact feature to add would be a "Bi-Directional Smart-Actuator Dashboard."
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.
The is a specialized, often free software utility designed for deep-level diagnostics on General Motors vehicles, typically used in conjunction with low-cost ELM327 OBD2 interfaces . Overview of the Tool