Theory Of Operation
WARNING: This page is about a different car, the 2016 RAM 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
The purpose of the diagnostic is to check the run position circuit for low or open circuit electrical failures by continuously monitoring the ON/OFF signal state. The TCM uses the run position signal as a general OBD enabling condition. If the run position signal state is OFF while the engine is running for a calibrated amount of time, a DTC will be set.