Theory of Operation

WARNING: This page is about a different car, the 2011 RAM Pickup. However, it is still accessible from the selected car via links, so may be relevant.

The Transmission Control Relay is used to supply power to the Transmission Solenoid/Pressure Switch Assembly and to the PCM when in normal operating mode. The purpose of the Transmission Output circuit is to allow the Transmission Control System to turn off the power to the Transmission Solenoid/TRS Assembly in event that the transmission should need to be placed into "limp-in" mode due to a DTC.

After a PCM reset, (ignition switch turned to the run position, or after cranking the engine) the Transmission Control System verifies that the Transmission Output circuit is open by checking for voltage on the Transmission Output circuits before the Transmission Control System request for the circuit to be powered up. The request is sent by a direct circuit control from the PCM to the TIPM. If voltage is detected on the Transmission Output circuits before the request is sent, the DTC will set.