vujkekv

Hi friends. I need your help. I discovered a big battery drain from my car. I have 2004 Porsche Cayenne Turbo 4.5. So, I bought voltmeter and found two fuses that drain my battery, fuse #40 which is for "Instrument panel, diagnosis" and fuse #41 which is for "Kessy control unit". Then I remove them to check if the drain will stop and it stoped, so I put fuse #40 back and everything was ok until I put fuse #41 and than drain started again from both units. My theory is that something in that Kessy is wrong and keep instrument panel awake and that is major drain. I also hear some noise from that area every 5/6 seconds (maybe more) when voltage from that fuse goes up so it must be something wrong with that Kessy unit. If I purchase another Kessy from other car, my key probably wont work so I want to know if I buy Kessy and the key from the same car, will it work on my car or I have to do something else? Any help or suggestion from would be appreciated! Thank you very much, best regards!

Avec

Is there a chance a door micro switch is stuck and the car doesn't know it is closed up? I don't have keyless entry, but it is my guess that Kessy unit sends a command to the cluster to allow it to go into "accessories" mode (first position on a regular key car).

vujkekv

Avec

Pull the Kessy out and see if there is a burnt resistor or something.

vujkekv

Stringbag

vujkekv

munkittrick

What are the odds that this turned out to be your problem? I'm experiencing EXACTLY the same thing and have had no luck with the dealer. Thanks!

vujkekv

Yes, that was my problem and I fixed it with change two mosfet’s on kessey unit. It was easy and cheap fix.

munkittrick

Man, that would be amazing! The Dealership has told me 4 different times that the handles are the cause of the drain, but ALL FOUR went out together? COME ON PORSCHE!?!?! I've had an "unfixable" battery drain that leads back to fuse 40 and 41 for a few months and the door handles have never worked as they should, so maybe this has been the issue all along! I'll try to track down the replacement FETs and resistors and get this done ASAP.

THANK YOU!!!

munkittrick

Sorry to be a bother again, but after replacing my MOSFETs and resistors, my draw is WAY down, but the doors still don't work with the buttons or the hand sensor. When you repaired your Kessy, were you handles working BEFORE the repair? Did they function properly AFTER the repair? Just wondering if fouled door handles are actually burning out the MOSFETs for people who have the same problem more than one time. Thanks again!

EDIT:
Also, I was told that my Kessy could communicate with the OBD-II scanner DEFORE the repair and I never have had any issue starting the car with the dummy key prior to the repair. It still functions AFTER the repair, but wasn't sure if there might be more going on. Are these symptoms that you had as well? Did your ignition and key FOB still function as expected even when the Kessy was using the two bad MOSFETs and resistors?