Gm Mode 22 Scan Tool By Terry -

Set the baud rate to match your hardware (typically 115200 bps for CAN-bus vehicles).

: Best for maximum data transmission stability and high logging speeds.

GM Mode 22 Scan Tool by Terry is a free, legacy diagnostic software utility designed for use with ELM327-based hardware interfaces

Setting up the scan tool typically requires a compatible interface cable and a laptop running the specific software developed and refined by the community. It is favored by the DIY crowd because it prioritizes function over form. The interface is lean and designed for performance, ensuring that data lag is minimized—a crucial factor when you are tuning a vehicle or trying to catch a momentary dip in fuel pressure. gm mode 22 scan tool by terry

While primarily a data logger, certain versions of these custom Mode 22 scripts allow for basic "active tests," such as cycling a cooling fan or testing an EVAP solenoid.

Here’s everything you need to know about using GM Mode 22 effectively.

What (like an OBDLink or ELM327) do you plan to use? Set the baud rate to match your hardware

If you are running a 4.8, 5.3, or 6.0 Vortec engine, or a classic LS1/LS6, the GM Mode 22 Scan Tool is your best friend for two specific scenarios:

It unlocks access to PIDs like "Oil Pressure" (which many GM trucks don't report over standard OBDII), "Transmission Fluid Temp," and "Desired vs. Actual Idle."

This feature transforms the tool from a "code reader" into a "repair tool," perfectly aligning with the persona of Terry. It is favored by the DIY crowd because

Among the DIY community, one specific utility has been a long-standing recommendation: the . What is GM Mode 22?

This guide covers what Mode $22 is, how Terry’s tool works, and how to use it for advanced GM diagnostics. What is GM Mode $22?

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.

Depending on the specific version of the script or software patch you deploy, it generally supports: