Because these codes are proprietary, they are often guarded by manufacturers or sold for high fees. Terry's scan tool was developed to give enthusiasts a way to request this data without needing expensive dealership equipment like the GM MDI 2 . Why Use the "Terry" Version?
Automotive diagnostics have come a long way from the days of reading flashing check engine lights. For General Motors (GM) enthusiasts, tuners, and mechanics, accessing deep vehicle data is the key to unlocking performance and troubleshooting complex issues. While standard OBD-II scan tools provide basic emission-related data, they barely scratch the surface of what your vehicle's Electronic Control Units (ECUs) actually know.
: Run the executable file. Inside the connection settings, select your designated COM Port and set the baud rate (typically 38400 or 115200 for ELM327 devices). gm mode 22 scan tool by terry
In a world where automotive software is increasingly locked behind subscriptions and expensive handheld units, the GM Mode 22 Scan Tool by Terry remains a testament to the power of community-driven diagnostics. It provides professional-grade insights for the price of a few parts, ensuring that older GM vehicles stay on the road and perform at their peak. Whether you are a weekend warrior or a dedicated tuner, having this tool in your garage changes the way you interact with your vehicle's computer.
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 Because these codes are proprietary, they are often
Select the specific PIDs you want to monitor (e.g., fuel trims, knock retardation, timing advance) and hit capture. You can export this raw hex or parsed data directly into CSV format for analysis in software like MegaLogViewer or Excel. Why Enthusiasts Prefer It Over Retail Scanners Generic Handheld Scanner GM Mode 22 Tool by Terry Cost $30 - $100 Free / Low-cost software + basic adapter Data Depth Basic emissions PIDs only Full GM-specific DIDs (ABS, TCM, BCM) Refresh Rate Slow (1-5 Hz) High-speed packed data (20-50+ Hz) Customization None (Hardcoded) Open tables; user can manually add hex addresses Logging Rarely supported or limited Advanced CSV export for tuning integration Safety and Best Practices
Key features
“If you’re still trying to diagnose transmission or ABS problems with a generic code reader, you’re guessing. Mode 22 turns guessing into graphing. Invest in a real scan tool, learn a dozen key PIDs, and you’ll fix in one hour what used to take three.”