Went to the track and learned that the coolant temp sensor issue I had pop up last track day was the red herring in my limp mode case, which was actually caused by the brake boost vacuum sensor.
I simultaneously learned (the hard way) that BMW engineers placed the un-shielded vacuum sensor directly below the brake fluid reservoir, and the overflow that happened when pushing back caliper pistons a couple months ago soaked said sensor in brake fluid, leading to a total of four warmup laps at the full track day of 7 sessions today (each capped by limpage).
To add insult to injury I broke the coolant bleeder screw off sending a coolant geyser of coolant onto everything including myself (It was pretty cool looking though), when I decided to bleed since I had replaced the coolant temp sensor earlier this week.
I did manage a personal best sector 3/3 on one of the warmup laps though somehow so it was looking like a good day of progression...what a day
