Theory Of Operation
WARNING: This page is about a different car, the 2013 RAM 3500 HD and 2013 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The Fuel Lift Pump Control circuit is a low side driver inside the Powertrain Control Module (PCM). The PCM sends a ground signal to the Power Distribution Center (PDC). The PDC then sends a 12 Volt feed to the Fuel Lift Pump. The Fuel Lift Pump grounds through a dedicated ground circuit. The MIL lamp and ETC lamp will illuminate immediately after this diagnostic runs and fails. During this time, the customer may experience engine stumble/stall or low power due to lack of fuel supply to the high pressure system. The PCM will turn off the MIL lamp once the diagnostic runs and passes in four consecutive drive cycles.