Diagnostics of Individual Air Fuel Ratio Cylinder Imbalance
https://www.thefreelibrary.com/Diagnostics+of+Individual+Air+Fuel+Ratio+Cylinder+Imbalance.-a0531111148Ford has filed patents on this technology, a couple of which are attached to this post.
DTCs
P219C Cylinder 1 Air-Fuel Ratio Imbalance
P219D Cylinder 2 Air-Fuel Ratio Imbalance
P219E Cylinder 3 Air-Fuel Ratio Imbalance
P219F Cylinder 4 Air-Fuel Ratio Imbalance
P21A0 Cylinder 5 Air-Fuel Ratio Imbalance
P21A1 Cylinder 6 Air-Fuel Ratio Imbalance
P219A – Bank 1 Air-Fuel Ratio Imbalance
P219B – Bank 2 Air-Fuel Ratio Imbalance