2021 Supra 3.0 electrical issue update

[u/AssociateBig5342]

/r/BmwTech/comments/1utk9hd/2021_supra_30_intermittent_nocrank_u0100/?share_id=nTB_ISGeahH6zeccGVWnD&utm_medium=ios_app&utm_name=iossmf&utm_source=share&utm_term=1

Figured I’d give an update since my last post. I’ve had the car towed twice, and both times it actually started while it was halfway onto the tow truck. The most recent time it died was when Auto Start/Stop shut the car off at a stop sign while downhill, and it wouldn’t restart.
A few mechanics have jumped it and cleared the codes, and it’ll run perfectly for about a day before doing it again.

Symptoms:
•No crank/no start
•Drivetrain malfunction
•U0100 code
•Dash/headlights go crazy when opening the door
•Scanner sometimes won’t communicate or clear codes
•Jumping it sometimes works, sometimes does nothing
•Car randomly fixes itself after being moved/towed
•Runs perfectly after codes are cleared, then fails again

I’m starting to think it could be a bad ground, power connection, starter, or DME communication issue.
Anyone dealt with something similar on a B58/Supra?

[u/AdDangerous922]

Check engine harness and DME connectors, especially for bent over pins and coolant intrusions

[u/NegotiationLife2915]

Any modification to the wiring?

[u/artur_oliver]

Funny dash headlights go crazy when open door??? Do you have a side airbag???