kvec

New to me 2011 CTT has started giving me an intermittent "Key Not Recognized" when driving. Will go 10-15 minutes at a time with nothing, but then will cycle through once every 2 seconds or so. Rinse and repeat for as long as you're driving.

iCarScan shows FR exterior lock button pressed intermittently (cycles yes/no in the data stream) and RL button pressed constantly. FR button actually works if you try it, RL does not. FL also doesn't work, but data stream shows it not actuated so I'm going to let that lie for the moment.

Yesterday did a little digging and noticed the two exterior door buttons in question had holes in them, pulled them off and they were filled with water. When I pulled off the FR button the car started locking itself repeatedly. Drove in the car afterwards and the "Key Not Recognized" messages continued pretty repeatedly. Probably got 30-50 separate red screens over the course of a 3-hour drive.

Thinking it's going to mean replacing the buttons. Anyone know how doable that is? Will I have to replace the entire handle? Any other thoughts?

A few notes on diagnostics I've already tried:
- Replaced both batteries in keys, have independently tried both keys. Seems independent of key.
- Have tried putting the key anywhere in the car. iCarScan shows a strong signal from each key and both antennas.
- Doesn't seem related to proximity to phone or buildings, etc. Have had the issue in rural areas, in cities, etc.
- Replaced the car battery 2 weeks ago with a brand-new AGM, has not changed the symptoms.
- Replaced the alarm siren module yesterday to solve a separate problem (hazard lights flashing upon lock). That solved the hazard lights problem but doesn't appear to have impacted this.

kvec

UPDATE: Pulled the (rubber? silicone?) off the buttons, flushed out the water with compressed air and some WD-40, let them dry overnight and covered them with electrical tape under the door handle trim. Problem seems to have subsided for the moment, so I’m thinking it’s an issue with the buttons shorting from the water.

Anyone have any sense of how hard it would be to replace the buttons? Presumably have to take off the door handle. Paging @deilenberger ?

Eskimo1

Wow, that's a PITA!.. Glad to hear you're on the right track though.

normfly

kvec,
Did you solve this? I am having similar issue: "Key Not Recognized" flashes along with chimes every 2-3 seconds while driving. Torturous. I've gone so far as to take the batteries OUT of BOTH fobs, power down all cell phones, laptops, etc anything with cell or Bluetooth. Turn the ignition with a dead/dumb fob and still the error message is there. I am a 8 hours drive from a dealership, so that's not really an option.

deilenberger

I think his message gave you some strong clues on how to start diagnosing it. First you need a Porsche capable code reader (Durametic and iCarScan are the two most popular ones), then I'd suggest a subscription to AllDataDIY - it's cheap and really a valuable tool.

He found error codes indicating that the KESSY system thought his external door handle button was being repeatedly pressed - and this might have triggered the fault message on the dash (if the KESSY was expecting to see an external key since the external button was being pressed.)

BTW - Welcome to the forum. Some hints for getting the most out of it:

- Better questions = better answers. The more detailed your question is - and carefully thought out - the more likely someone will take the time to reply and give a reply that's relevant to the problem at hand.
- Including the year/model of your Cayenne in EVERY message is a good thing. If you're a paid member you can do that automatically with your "SIG" - having that info helps people again - give a reply that's relevant.
- Including your location, or even - gasp - your actual name in a message might find someone close to you that may be able to help. That's more likely if they think they're talking to Norm Smith rather than NormFly.

Good luck! Dunno how recently kvec has been on the forum. Usually worth checking that too.

normfly

ddellenberger: I'm familiar with boards, but thanks for the insight. You may not have read this as closely as I did: "Problem seems to have subsided for the moment, so I’m thinking it’s an issue with the buttons shorting from the water." My question remains: Did that solve the issue? Meaning was there anything else that *did* solve it so I can replicate his findings *in addition to* the short. I've read dozens of threads on this topic, none of which mention anything about the KESSY. So this is the thread I'm trying to track down to conclusion. And I'll just have to hope kvec checks in. Make sense. Thanks.

kvec

Apologies for the delay here. Diagnosed it to my satisfaction, but the fix isn't fun. Turns out the issue was the short in the FR button. The button is integrated in the handle, so if there's an issue with it, the only way to fix it is to replace the handle itself.

I managed to stop the symptom by disconnecting the electrical connection from the handle to the car. Handle still works and the keyless unlock still works on that door. It just doesn’t lock when you hit the button, but it hadn’t been working anyway because of the short. I may replace the handle someday, but it’s an expense I don’t feel really adds much to the car so it’s low priority.

Interesting lesson here: If you find that your car is saying "Key Not Recognized" while you're inside with the key and the car *on*, it’s likely one of the keyless entry buttons is being activated. Apparently the error message was originally meant to convey that someone was hitting the button without the key in their pocket.

You can diagnose the issue with iCarScan by looking at the data stream. It’ll show all five buttons (incl. trunk) and tell you the signal strength of the antennas. I’d start there to see what kind of oddities you can find.

Ken

kvec

This was the issue. When the button is pressed, the car expects there to be a key outside the car right by the handle. It's basically saying "Sorry, don't see a key there," even though the car is going 75mph down the road or whatever.

deilenberger

Ken - thanks for getting back to us with the solution. Too many times people come, dump a problem, get a lot of ideas from people - and we never hear from them again. Glad to see you're not "that guy.."

kvec

Thanks, Don. Appreciate all the work you put in here. The DIYs in particular have been incredibly helpful (oil + TC fluid changes, alarm module; you know, the fun stuff).

Ken

normfly

Incredibly helpful and I'm almost certain the culprit behind my issues. Thanks guys!!

Tim Wasmer

I will drop my .02 in here. I was having the same issue. I finally took it to the dealer and there were no codes. So we reprogrammed the keys to the car and the issue seems to have gone away. Mine is a 2011 CTT with 89k on it.

It was frustrating as heck that is for sure!

clorigo

I had this issue on my 2011 Panamera Turbo -- I finally gave up! I no longer own it, but boy I wish I would have come across this thread years ago!

Tim Wasmer

Well mine is back. Went about a week and a half. PWIZ at the dealership shows nothing. Very frustrating.

kvec

Tim - Have you tried checking yourself? iCarScan for me helped triangulate which handle it was that was causing the issue. From there it’s a matter of figuring out which road to go down to fix it.