Gm Mode 22 Scan Tool By Terry |top|

Turn the ignition to ON (engine off for sensor checks) or start the engine. Click “Connect” or “Scan Mode 22”.

Is the software perfect? No. You’ll need patience to find a working download and to configure your serial connection. But once it’s running, you will wonder how you ever diagnosed a GM “Check Engine” light without it. gm mode 22 scan tool by terry

Open “GM Mode 22 Scanner by Terry.exe”. Set the correct COM port and baud rate (8192). Turn the ignition to ON (engine off for

Plug your USB ALDL cable into the port. Pins A and B (top two rightmost pins) are typically the ground and data lines, but quality cables auto-detect. Open “GM Mode 22 Scanner by Terry

For the price of a USB ALDL cable (around $40-60), you can have dealer-level diagnostics from the early 1990s. Terry may not have a corporation or a tech support line, but his Mode 22 scan tool has kept more vintage GMs on the road than any dealership recall. Download it, connect it, and finally see what your old GM is really thinking. The GM Mode 22 Scan Tool by Terry is community-developed software. Always verify compatibility with your specific GM ECM/PCM mask ID and use at your own risk. Incorrect bi-directional commands can damage sensors or actuators. When in doubt, consult factory service manuals for your vehicle.

Terry’s original tool was written for Windows 95/98/XP. However, modern versions or community updates run on Windows 10/11 in compatibility mode. Install the FTDI or Prolific drivers for your USB-to-serial adapter.