Scan Tool By Terry — Gm Mode 22

| Tool | Protocol | Price | Best For | |------|----------|-------|-----------| | | ALDL Mode 22 | Free | Budget, simple diagnostics | | Scan9495 | ALDL Mode 22 | $30 shareware | LT1/LT4 specific (94-95) | | TunerPro RT | ALDL + OBD-II | Free (donation) | Advanced tuning & logging | | ALDLLogger | ALDL Mode 22 | Free | Mac/Linux users | | Tech 1 w/ GM cartridge | All GM modes | $500+ used | Professional restoration |

| Feature | Benefit | |---------|---------| | Reads 100+ GM-specific PIDs | Injector flow rates, fuel rail pressure desired vs. actual, EGR position, fan clutch duty cycle | | Works with cheap ELM327 v1.4+ | No expensive Tech 2 or GDS2 required | | Logging & graphing | Compare data over time, diagnose intermittent issues | | Free / low cost | Often available as a downloadable .exe | | No internet required | Works offline once installed | gm mode 22 scan tool by terry

Though largely superseded by modern apps and GDS2 software , "GM Mode 22 Scan Tool by Terry" remains a nostalgic name for anyone who spent their weekends in a garage with a bulky laptop and a dream of fixing their own Chevy or Buick. | Tool | Protocol | Price | Best

For owners and technicians working on 1980s to mid-1990s General Motors vehicles (especially those with the 8192-baud ALDL data stream), the "GM Mode 22 Scan Tool by Terry" remains a legendary piece of DIY diagnostic software. Unlike generic code readers that only retrieve "Check Engine" codes, Terry's tool provides a deep, real-time look into the inner workings of early GM electronic control modules. Unlike generic code readers that only retrieve "Check

1994 C4 Corvette idles rough but no OBD-II codes. Solution: Use Mode 22 to view the IAC position and TPS closed-throttle voltage. The tool reveals a TPS voltage of 0.78V (spec is 0.45-0.65V) – adjusting the TPS fixes the idle.

Ready to Command.