In SCCM, we have a number of handy tools we can use to force SCCM clients to run processes remotely.  For example, there are scripts, right click tools, etc that can force the SCCM client to update it's hardware policies, or scan for updates.

I'm looking for a similar model to force SCEP clients to check for definition updates.  For example, a powershell script I could run to tell the SCEP client on a remote system to check for updates against the SCCM environment.  

Anyone have something like this?

You will need to use MpCmdRun.exe

https://technet.microsoft.com/en-us/magazine/gg131918.aspx

The basic usage at the command prompt is: 
MpCmdRun.exe [command] [-options]

%ProgramFiles%\Windows Defender\MpCmdRun.exe

You could run it with PSEXEC to run it remotely.