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 Transmission Control Relay is used to supply power (Transmission Control Output) to the Transmission Solenoid/TRS Assembly when in normal operating mode and to pins C1-26, C1-27 and C1-28 of the PCM. The purpose of the Transmission Control Relay is to allow the Powertrain Control Module (PCM) to turn off power to the Transmission Solenoid/TRS Assembly in event 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 engine) the PCM verifies the Transmission Control Relay contacts are open by checking for voltage on the Transmission Control Relay Output circuit before the Transmission Control Relay is energized. If voltage is detected, the DTC will set.