Chosen Solution
I replaced my MBP’s battery. It boots, but turns back off after anywhere between 1 and 10 seconds of usage, while connected to charge. I got the battery from iFixit and followed the installation guide without any obvious errors. What am I doing wrong? Here’s what I’ve tried: resetting SMC – no effectrunning diagnostics (holding D during boot) – no issues foundusing Safe Mode – no effect I’m limited in my diagnostic abilities due to the fact that the laptop shuts off before I can really do anything. edited: clarity
Current working hypothesis is that the battery was DOA. I’m returning it to iFixit.