Gm Mode 22 Scan Tool By Terry _hot_ May 2026
"GM Mode 22 Scan Tool by Terry" is legacy freeware commonly bundled with ELM327 OBD-II interfaces for reading enhanced GM-specific diagnostics. Designed for older operating systems, it provides access to specialized vehicle data parameters not available in standard generic OBD-II modes. For modern GM vehicles, users typically transition to factory-level tools like the OEMTools GM MDI or advanced third-party scanners. Interfuse LLC. Obd2 elm327 v1.5 usb can bus scanner | PDF - Slideshare
Who is Terry? The Story Behind the Legend
In the world of GM tuning and diagnostics, “Terry” is a whispered name of respect. While multiple developers have created Mode 22 interfaces, the version most widely known as “the Terry tool” or “Terry’s Mode 22 Scanner” originated from the early 2000s GM EFI tuning forums (like thirdgen.org, DIY-EFI, and Gearhead-EFI). gm mode 22 scan tool by terry
Terry was a community programmer who recognized that professional tools like the Tech 1 or Vetronix Mastertech were expensive, rare, and locked to dealer use. He developed a software-based solution—often distributed as a freeware/shareware Windows application—that, when paired with a simple serial or USB-to-ALDL cable, could perform miracles. His tool demystified the $EE, $8D, $42, and $58 masks used in GM vehicles from the mid-80s to the mid-90s. "GM Mode 22 Scan Tool by Terry" is
Key Models That Benefit from Terry’s Mode 22 Tool: Who is Terry
- 1985-1992 Camaro/Firebird (Tuned Port Injection)
- 1992-1996 Corvette (LT1/LT4)
- 1993-1995 Camaro/Firebird (LT1)
- 1987-1995 GM Trucks (C/K series, Suburban, Blazer) with TBI or Vortec
- 1986-1993 Buick Grand National / T-Type
- Early 90s Cadillac Northstar systems
1. Full Sensor Data Grid
View every analog and digital input the ECM sees:
- Coolant temperature (actual degrees, not a vague gauge)
- Manifold Absolute Pressure (MAP) in kPa and voltage
- Throttle Position Sensor (TPS) voltage and percentage
- Oxygen sensor cross-counts (not just rich/lean)
- Vehicle Speed Sensor (VSS) pulses
- Knock sensor retard (in degrees)
- Long-term and short-term fuel trim per cylinder bank