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 T41 (C1), T42 (C2), T3 (C3), T1 (C4), T2 (C5) Sense circuits communicate the shift lever position to the Transmission Control System. Each circuit is terminated at the transmission by the Transmission Range Sensor (TRS) switch. Each switch can be open or closed depending on the shift lever position. The Powertrain Control Module (PCM) decodes this information and determines the shift lever position.

Each shift lever position has it own unique combination of closed and open switches, this is called PRNDL code. There are five switches, therefore: there are many possible combinations of open and closed switches (codes). There are 12 valid codes: two for neutral, one for each gear position (5), and five temporary (transition zone) codes. The remainder of the codes should never occur, these are called invalid codes.