I suspect you can replace JUST the control module without removing the intake manifold. BUT… the control module is buried on the driver’s side of the engine under a spaghetti of vacuum hoses, etc. Here’s what it looks like with the intake manifold removed.
My repair MO is simple — even BMW parts are cheap, compared to my time and labor — so I replaced all 6 glow plugs and the controller at the same time using the ECS Tuning - Glow Plug Service Kit that includes 6 Bosch glow plugs, the control module, 12 intake manifold gaskets and the throttle body gasket.
More details at
https://xoutpost.com/bmw-sav-forums/...ol-module.html
Funf Dreisig