AFM/DFM Disabler GMAFM DFM DISABLER GM Eliminate AFM DFM on your GM vehicle with the Range Technology AFM DFM Disabler. Plug and play design keeps your engine in full power mode for smoother performance, better throttle response, and improved reliability. The Range Technology AFM DFM Disabler for GM vehicles is the perfect solution for drivers who want full control over their engines performance. This simple plug and play device disables GMs Active Fuel Management (AFM)