Unlike modern generic scan tools that use a standard J1850 or CAN bus, Terry’s tool sends a specific to the ECM. The ECM responds by dumping a packet of 32–64 bytes of raw RAM data. Terry’s software then decodes that raw hex data into human-readable values.
(Enhanced Data), which is a proprietary diagnostic mode used by General Motors to provide more detailed information than the standard legislated OBD-II Mode Functionality gm mode 22 scan tool by terry
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. Unlike modern generic scan tools that use a
Find the 12-pin connector. On most F-bodies and Corvettes, it is under the dash left of the steering column. On trucks, it may be above the gas pedal. (Enhanced Data), which is a proprietary diagnostic mode
The GM Mode 22 scan tool performed well during testing, with reliable connections and accurate data readings.