VDIAGTOOL D501 GM Bidirectional Scan Tool Full System

The D501 is a GM-only diagnostic tool, so it talks to every module the truck actually has instead of stopping at generic OBD2 powertrain codes. Plug it into the DLC, run AutoVIN, and it pulls the VIN and loads the module list for that vehicle: engine, transmission, ABS, airbag, EPB, HVAC, 4WD, suspension and lighting. Coverage runs 1996 through 2026 Chevrolet, GMC, Buick and Cadillac.

For transmission work the value is the TCM side. You can read and clear transmission DTCs the generic reader never sees, then watch live data in graphed streams while the vehicle is moving - line pressure command, solenoid state, input and output shaft speed, TFT and gear commanded versus gear attained. That is how you separate a slipping clutch pack from a solenoid or a wiring fault before you pull the pan on a 4L60E, 6L80 or 8L90.

Bi-directional control lets you command components straight from the tool rather than guessing. Actuate fuel pumps, cooling fans, door locks, windows, sunroof and wipers to confirm whether the actuator itself is dead or the circuit feeding it is. The reset menu covers 28+ GM service functions including throttle body relearn, crankshaft position sensor relearn, oil life reset, ABS bleeding, EPB retract, SAS, TPMS, battery registration, injector coding and air suspension calibration.

It runs on CAN FD for late-model buses and includes the J2534 pass-thru protocol for GM if you want to reprogram with GM's own OEM software - note that the GM software subscription is bought separately from GM and is not included here. Software updates are free for the life of the tool with no subscription. Ships as the D501 interface; it pairs over Bluetooth to an Android device.