The module has likely failed. Change all the plugs and module, otherwise you'll be be removing the manifold again like I had to.
https://xoutpost.com/bmw-sav-forums/...d-all-6-a.html
Be sure to have extra coolant, the module is underneath a coolant hose, I had to losen it to get to the module, and you'll have to add coolant and bleed the system if you can't get it out without removing the coolant hose