Theory of Operation
WARNING: This page is about a different car, the 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The Engine Oil Pressure (EOP) Switch is used by the Powertrain Control Module (PCM) to monitor the lubricating oil pressure. If the oil pressure drops below the engine protection limit, the switch will close and cause the fault to log. The Oil Pressure Switch is normally closed when the engine is not running and open when oil pressure is present. When the fault is set, the PCM illuminates the MIL light. The PCM will turn off the MIL light after the diagnostic runs and passes in four consecutive drive cycles.