Gm Mode 22 Scan Tool By Terry //top\\ -

In the world of OBD-II diagnostics, most basic scanners rely on "Mode 01" data, which is the federally mandated generic information required for emissions testing. This includes basic engine RPM, coolant temperature, and oxygen sensor readings. However, GM vehicles utilize , a proprietary diagnostic mode that allows for "Enhanced Data."

This feature transforms the tool from a "code reader" into a "repair tool," perfectly aligning with the persona of Terry.

In the automotive hobbyist community, independent developers often create specialized software routines or hardware configurations to bypass expensive dealership equipment like the Tech 2 or GM MDI.

A high-quality OBD2 adapter is required. While cheap ELM327 clones sometimes work, adapters featuring original STN1110 or PIC18F25K80 chips (such as the OBDLink LX/MX series) offer the timing stability required for custom hex commands. gm mode 22 scan tool by terry

The is a highly specialized, free legacy diagnostic software program designed to extract advanced manufacturer-specific data from General Motors vehicles. While standard OBD-II tools are limited to generic emissions data (Modes $01 through $0A), this utility leverages GM’s proprietary Mode $22 protocol to request specific diagnostic data identifiers (PIDs) directly from the Powertrain Control Module (PCM).

Terry’s Mode $22 tool usually operates via common hobbyist interfaces:

You cannot access Mode 22 with a $20 code reader. Terry recommends: In the world of OBD-II diagnostics, most basic

In the diesel community, the tool gained a particular reputation for working with GM's Duramax engine, especially for reading fuel rail pressure and other critical diesel-specific parameters using Mode 22 requests.

While Terry's tool was revolutionary at the time, diagnostic technology has moved forward. If you cannot find a working copy of this software, or if you have a newer vehicle, consider these alternatives:

By tapping into Mode $22, you can read real-time sensor voltages, switch states, and module statuses that standard OBD2 tools completely ignore. Understanding "Terry's" Mode $22 Tool The is a highly specialized, free legacy diagnostic

GM Mode $22 Scan Tool by Terry: The Ultimate DIY Diagnostic Guide

Toggle the baud rate setting between 9600, 38400, and 115200 until characters stabilize. Too many Mode 22 PIDs are being requested simultaneously.

This software isn't just another code puller. Its power lies in its diagnostic depth:

“That’s the power of Mode 22,” says Terry. “Generic data would show RPM and VSS, but you’d never see the slip. You’d replace the torque converter unnecessarily.”