Theory Of Operation
WARNING: This page is about a different car, the 2015 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.
The objective of the Dynamic Crankshaft Fuel Control (DCFC) is to reduce the fuel as much as possible during a cold start (open loop operation). The Powertrain Control Module (PCM) monitors the variation in CKP Sensor speed to determine engine idle roughness. The DCFC monitor begins adding or subtracting fuel in an attempt to attain optimal fuel/air ratio at idle with out causing engine roughness.
The monitoring and set conditions for the P050D and P150D DTCs are identical except for one difference. The P150D will set if the throttle was opened during cranking.