Torque Reduction Link (TRD)

TRD LINK
DESCRIPTION
The Torque Reduction Link (TRD) is a wire between the PCM and TCM that is used by the TCM to request torque management. Torque management controls or reduces torque output of the engine during certain shift sequences, reducing torque applied to the transaxle clutches.

OPERATION
The torque management signal is basically a 12-volt pull-up supplied by the PCM to the TCM over the Torque Reduction Link (TRD). Torque management is requested when the TCM pulses this signal to ground. The PCM recognizes this request and responds by retarding ignition timing, killing fuel injectors, etc. The PCM sends a confirmation of the request to the TCM via the communication bus. Torque reduction is not noticeable by the driver, and usually lasts for a very short period of time.
If the confirmation signal is not received by the TCM after two sequential request messages, a diagnostic trouble code will be set.