What does it mean?
The transmission control module (TCM) uses a combination of sensors (speed sensor, TPS throttle position sensor, crankshaft position sensor etc … ) and the ECM to monitor and adjust various function of the transmission system. In this code, it describes a malfunction within a specific circuit. The output control circuit is a specific circuit within the TCM electrical system.
Locations, specific procedures and desired values will all depend between manufacturers, so you most definitely will need a service manual to diagnose this code. You may find that this particular circuit is referring to a circuit within the engine speed sensor, AKA: Crankshaft position sensor (CPS), monitoring system. The TCM monitors many things, including engine speed to determine shifts among many other things.
The TCM monitored a certain value go outside of the desired values and communicates to the ECM to activate the code and your engine light comes on.