Theory Of Operation

WARNING: This page is about a different car, the 2017 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 to the solenoids and pressure switches when the transmission is in normal operating mode. The relay output is fed back to the TCM. It is referred to as "Transmission Control Relay Output". This circuit does not supply the primary power to the TCM, but does supply power to the solenoid control circuits in the TCM. It is also used as a sense circuit to verify relay function. When the relay is off, no power is supplied to the solenoids or pressure switches and the transmission is in "limp-in" or "default" mode. Note: Inadequate Transmission Control Relay Output voltage can cause DTCs P0846, P0869, P0871, P0876 or P0988 to set. This does not indicate an internal transmission or solenoid/TRS problem. Repairing the P0882 fault should eliminate the related DTCs.