Comfort Control Module fault - can this be draining my battery?

A while ago I got this fault. Familiar with what needs to be replaced and haven't done it solely as I haven't had the time to go to the dealer and get it reprogrammed. However, I wound up with a dead battery . Alternator test it out fine - putting out 14.7 volts. Replaced battery as it was almost 5 years old. Used an AGM replacement in stock size. Battery was dead within a week - and the car wasn't driven much. Tried to charge it with my smart charger and it wouldn't charge. Turns out the battery was a dud. Replaced it with the same battery . Didn 't drive it much and again dead battery . Turns out this one was bad too. So - while I'm pretty sure it was two bad batteries - I'm wondering if the damn comfort control module is draining them. I replaced the second dud with a led acid battery and have it on my battery tender . So we'll see how that goes.

What is the fault with the comfort control module? And it's doubtful if two AGM batteries were duds out of the box.

C127 error code. Gives a system fault on dash. Goes away when using turn signals and then comes right back. As for the two duds - yeah I'm a bit skeptical - but they tested the first and it had bad cells. My charger said that the second had a bad cell and wouldn't charge it anymore. So, who knows.

I wish my AllDataDIY hadn't expired 2 days ago - I'd love to look that code up in their listing of Porsche codes for the Cayenne .

You can go old school and measure the current across the fuse that feeds that control module (with the car off) to see if you are drawing current. If you aren't seeing any, check for current draw at the battery with the car off. You shouldn't see more than a few milliamps at the battery . You can then go fuse by fuse to see what circuit is causing the draw.

Great suggestion - one other thing if you're going to do this. After shutting the car down and opening the driver's door to access the fuse panel - wait at least 15 minutes for all the car's computers to power down. They do that after about 14 minutes of no electrical activity (like opening a door..)

I see this is an older thread but I'm wondering if there was a solution to the dead battery issue and maybe related to a comfort module? I'm having the same issue. Dead battery with 3 to 24 hours. Local mechanic traced it to a "comfort module" but after replacing, same issue. Research shows a few modules are referred to as "comfort" modules, but one is specific to the rear hatch. So, was there a result to this issue? Thanks

The other people in this thread have been inactive for over 6 months, so I doubt if they will see your question. Sorry. And stop by the New Member Introductions and introduce yourself and your car -- we love photos!

OK, Thanks. Just added a post to the newbie site...

One suggestion - since your mechanic has narrowed it down to one of the various "comfort" modules - how about unplugging each of them and seeing if the battery still discharges? You could start with all of them unplugged, then plug them in one by one until you find the one that causes the battery to discharge.

Yea, great suggestion. We are currently getting the battery charged back up to full, then start unplugging modules. We know, one of the modules is in the right rear and we "think" the other one is there too. Thanks for the input.

I looked on AllDataDIY to see if they had a layout diagram locating all the diagrams (I know they have one for my Cayenne ) - but haven't found it yet. I did find info on R&R of several of the modules. Besides the rear wall of the trunk (the wall against the engine compartment) where Porsche has been known to hide things, I know some of the top modules on the boxster is located up under the dash on the drivers footwell.. and there may be others in the "frunk" - behind some of the fuzzy liner. I'm assuming this is a Cayman - what year? At least in a Cayman it's unlikely to be the main body module that's located under the drivers seat and gets flooded when people leave the top down in a downpour.. Good luck - please let us know how it works out..

Ah - I did find these - these are connector points - some of which connect to modules. Find the connector, find the module sort of thing: HTH,

I was just going to make a separate post and I see your comment. Yea, I just came from the Porsche mechanic, and we spent about 45 minutes searching, where the "comfort" module is. We even got the shop next door searching with us. We never came across the diagrams you posted so I'll research from those and also do my second posting. Thanks. Oh, this is a photo of it:

On that module - it's fairly obvious the large plug bottom right side - with a brown and red wire are the battery connection for it. The others are likely outputs and control circuits. The ones along the top look like much smaller wiring so they're probably control circuits and Canbus connectors.

I believe, I found the module. The P mechanic looked under the dash, drivers side and said he didn't see anything that looked like it. I took a look later on and found one with the same plugs going in with same color wires as the photo (in previous comment). I just can't see the part number. 7L5937049 is the number but there are letters at the end like D or F or AA . So, I think I need to pull it out to see what letter at the end is. (Just a plastic frame work thing in front of it). But will check with the mechanic first. Thanks for all the input. Update with hopefully a resolution soon.

The last letter or number is typically in Porsche fashion - the revision number for the device in question. Starts with A and goes to.. (I think the coils are out around 20 now..)

OK, an update and maybe resolution. I replaced the module under the dash. Part number shows as a body control module, but I've also seen it as a comfort module. The P mechanic said to first only plug in the power wires and nothing else. A day later, I still had a full battery . So, I plugged in all the other wire harnesses and a few days have gone by and still starts every time. Only thing is, I started it everyday to move it from one side of the driveway to the other to get cars out. So, it only would have charged the battery for a few minutes. It's never gone 3 days before without an issue. So, BCM or Comfort module, under the dash, would be a good place to start looking, if anyone else has this problem. Thanks for the help and guidance.