2016 750i thermostat

[oupatton]

1d2008 code, says map thermostat stuck open. How much of a pain is it in this car?

[Raimo5]

Ah, the dreaded map controlled thermostats. If I'm not mistaken, then there is an open bulletin on N63 map thermostats. They not only fail and seize internally, but the connection terminal actually starts leaking coolant and it will wick up through the engine wiring loom in to DME connection. There it will leak in to your DME and fry it. You need to have it checked. In fact, every N63 owner should check their map thermostat plug every now and then. Your map controlled thermostat might even be okay internally, but you will start getting different errors when you start accumulating coolant damage inside DME.

It's amazing that this is still the case 20+ years later. This issue first came up with M62 engines where map controlled thermostats were introduced.