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JackintheBoxster
Any thoughts on this would be appreciated. I recently had the control unit below the driver's seat replaced because of flooding by my trusted indy mechanic, and a new key from the local (less-trusted) dealership. Everything works more or less ok except the key stopped working remotely to unlock the doors (at first it only would not remotely unlock the trunks). Now I have to unlock the door manually and when I do, unless I start the car quickly, the flashers start going. This latter business, I assume, has something to do with the alarm system.
My mechanic cannot figure out what it is -- and this is a very good guy, he's replaced the engine in this car and done quite a bit of work on this car and our BMW 3 series over the last 10 years, so I trust him. He says I might go back to the dealer and ask them if they've badly programmed the key or something, but I (and he) do not have much faith that they will do anything other than figure out a way to gouge me out of money. Any advice on this from the board? I have to say that for a 15-year-old car, this is a minor inconvenience, particularly compared to the engine dying at 70 miles an hour a few years ago, but I'd like to fix it if it can be done without too much bother.
The alarm sounding if you unlock the door with the key blade and if you do not start the car within a short time -- seconds -- is normal. Whenever my cars are serviced often the dealer SM will put the car outside and locks the car with the key hidden inside and then later in the evening I arrive to pick up the car and I open the door with the valet key. If I don't insert the valet key in the ignition and turn the key on the alarm sounds after IIRC 10 seconds.
Even though the key is new that doesn't mean it can't go bad but it doesn't read like a bad key. The symptoms/behavior describe a worsening problem. This doesn't really read like a key module circuit board problem.
Knowing the alarm module has been replaced due to water in the cabin the behavior then suggests to me a deteriorating security module. Well, not the module directly but its electrical connections. Probably not from more water getting in the cabin but from the moisture that remained in the cabin from the previous exposure to water.
It is possible corrosion is occuring at the alarm module connector(s) and as some pins/contacts have become corroded this has resulted in the symptoms. I trust the doors are dry and the bottoms of the doors are not damp even after a washing or the car being outside in the rain?
It is also possible that with the proper Porsche diagnostics computer (or possibly a Durametric) one could query the security module for any error codes and these would provide more info that would help to confirm (or not) my "diagnosis" above.
Now it could be just the RF antenna that picks up the RF signal that the key transmits whenever you push a button. This antenna is not the same one that picks up the RFID RF signal from the RFID pill in the key module that allows the engine to start. The antenna that picks up the key module button presses is IIRC in the windshielf frame. But its connection is to the security module and this is where I would look -- with care! you do not want to static discharge into any of the car's electrical circuits! -- to see what the electrical connection is at the security module.