The "TPC Inactive" warning light has come on a couple of times in the past two days ON MY 997.1 S. It seems more serious than the light that comes on when a tire is low on air, or when a TPM goes bad, as it can't be cleared. Both times, it went away as mysteriously as it came. Does it sound like anything to worry about?

I've also had my CEL coming and going, but that's the result of my recent flash and 200 cell cats not playing together nicely (fault code 2196). I doubt it's related to the TPC, and there are no other fault codes stored. I may need to take it to the shop to check my O2 sensors, but I'd rather not have my mechanic spend time trying to solve a problem that no longer exists. That said, something must have triggered the TPC light.

 

Are you on your original tire pressure monitor sensors? If so, then you've probably got one or more batteries going dead and the sensors need to be replaced. OE parts are quite expensive, but there are some aftermarket alternatives that cost less.

 

Three out of four sensors have been replaced, so I know I must be about due with #4. I don't remeber that light going on with the others, which were changed one at a time. It does not cycle through the learning mode, which is what I thought it did before. I may as well change that last one, though I still have my doubts that this is what triggered the TPC Inactive light. I hope you're right. Thanks.

 

You can force it to cycle through learning mode by switching to "winter tires" mode and then back, forcing it to relearn.

 

Sorta thought that but it's nice to know, thanks!

 

I just reflashed the ECU, and the light reappeared. I think it's a gremlin related to the flash that just works itself out. I hope so, anyway. My fingers are crossed.