The P0599 code is often the thermostat wiring harness damaged, saturated with coolant, or wicked coolant up into the DME connector. Tear into that and see what you find. Post pics here if the cause is found.So, my 2005 E46, 137,xxx miles just threw code P0599. I decided to check the coolant level and it was low. I should note there haven't been any noticeable leaks. Advice/thoughts? Thank you!
You haven’t stated the model E46 you have, so I’ll just assume a 2005 330Ci.Any links on to look at the thermostat wiring harness?
Cool! (pun intended)UPDATE: So, I hedged myself and order a new thermostat just in case. Went to my INDY mechanic this morning, who I happen to be friends with. Looked at the wiring harness and didn't see anything remarkable. SO, we changed out the thermostat and all good. Thank you all be well!