Deleting Displacement on Demand/Active Fuel Management doesn't necessarily require a delete kit has to be installed. If your lifters haven't collapsed yet then they will hold up perfectly fine after removing DoD in the tune.
If you are installing a kit because of collapsed lifters then you will have to tune this way anyway.
Disabling DoD will save you money by preventing the common problem of eventual lifter collapse. The transmission life will be extended as well because there will be less shifting and hunting for gears.
Don't waste money on OBD adapters that fool the sensors and may cause dangerous driving conditions (speed sensitive steering). No need to unplug the brake booster sensor. Finally, don't be fooled by remote tune scams. Tuning DoD out is very easy to do with HPTuners.
Procedure:
Engine -> Fuel -> Lean/Fuel-Saving -> DOD dropdown menu
Set to Disable.
Engine Diag
Find DTC's related to cylinder deactivation. Found in P3400 and on. Uncheck SES Enable and set to No Error Reported.
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(Optional) Engine -> Airflow -> Variable Camshaft -> Desired Angle
Set VVT angles uniformly per column from 1000 to 3400rpm. This area is the light throttle/cruising area. Many of the positives of DoD delete, as far as throttle feel and torque, will be increased even more so.
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(Optional) Engine -> Airflow -> Variable Camshaft -> Intake Camshaft/Exhaust Camshaft
Set intake and exhaust minimums to 0 to allow for better torque.
Attached are stock and modified tunes with all changes mentioned applied as a comparison.