The Dynamic Fuel Management (DFM) system in 2019 K2XX trucks (and some late 2018 builds) is an evolution of AFM. It deactivates cylinders even more aggressively. Here’s what DFM is and whether deleting it is worth it.
Wait – Is This About K2XX or T1XX?
The true DFM system debuted in the 2019 T1XX Silverado/Sierra. Some K2XX trucks in 2019 use AFM (not DFM). However, late 2018 production trucks can have DFM.
For 2014–2018 K2XX trucks with the 6L80/6L80E transmission: AFM is the system used. DFM came with the 8-speed transmissions introduced in the redesign.
AFM Delete on K2XX (The Actual Common Issue):
The 5.3L EcoTec3 in the 2014–2018 K2XX trucks has AFM and uses the well-documented collapsing lifter design. These lifters can fail between 80,000–150,000 miles.
Why Delete AFM on K2XX:
- Prevents the AFM lifters from cycling, reducing premature wear
- Smoother throttle response (no switching between V4/V8 modes)
- Prevents potential oil consumption issues
Range Technology RA003B AFM/DFM Disabler – Plug-and-play device that keeps the engine running all 8 cylinders. Works on 2014–2018 K2XX trucks with AFM.
Fuel Economy Impact:
Disabling AFM typically costs 1–2 MPG on the highway. Most owners consider this a worthwhile trade-off for lifter protection.
Permanent Solution:
For a permanent AFM delete, an HPTuners or DiabloSport tune can disable AFM at the ECM level. This is the cleanest solution.
Have you deleted AFM on your K2XX? Share your experience!