Agreed, it won't be what it once was, but it wasn't a -40C deep discharge; that'll roast a battery in one shot. I'll keep an eye on its performance and replace when necessary.

The V1 is typically hardwire to the OBD2 port, but the cable was removed from the A-pillar by the body shop when they re-sprayed the DS door. It'll go back in when I have some time.

 

Hijacking my own thread

After the battery reconnection, all airbag/PSM/PASM warnings came and went as the car was driven. The TPM continues to read "TPM Inactive" with the tire pressure warning light and red !.

I have covered nearly 200mi since.

I have attempted a quick re-learn (ie., I didn't deflate and re-inflate the tires) but it doesn't enter learning mode after asking tire size. It just returns to the TPM menu. Durametric shows 8002 TPM Control Module Fault.

What's the internet's consensus?
A. Bad Battery - I'm not convinced; yes, it was drained, but it's been on a 2A charger/tender any time it hasn't been running. So there's no way the supplied voltage couldn't be sufficient.
B. Coincidental TPM module failure during flat battery / Flat battery for ~2 weeks broke the TPM module, and module needs replacement.
C. I need to get off the internet and do the full after-marked reset procedure.

 

Ignition switch often causes these symptoms - some electrical accessories will work while others won't, and it probably won't be consistent each time. I've seen the ignition switch start the car fine but no HVAC or sometimes no radio. You should be able to isolate it between the two with a little more investigating.

 

After an issue with a dead battery my ignition switch was also fried - it worked but would not release the key. All sorts of weird symptoms seem to be related to that module, and if yours is made in Australia, it's known for reliably failing. 15 minute replacement with few tools needed.

Did a prior owner code out the TPM, and now it has returned due to dead battery?

 

No, the TPM system reliably showed the pressure before this.