Key Fob battery/reprogramming

Recently the battery in my key fob died. No biggie, I bought another and replaced it. The strange thing is that it still doesn't work (now it lights up at least). I feel like I've changed this battery before without having to reprogram the key. Is it typical to have to pay for reprogramming when you replace the battery? -Shawn

Not 100% but I don't think that there is any programming. I thought I read somewhere that there is a small micro chip (that looks like a small tube Fuse) inside the key Maybe you dropped that chip when you opened your key to replace the battery?

What do you mean by "it still doesn't work", can't remotely unlock and lock the doors or can't start the engine? If it's the former then something has gone wrong with the circuitry, you may then need to purchase a new key fob to be programmed to the car, if it's the latter, perhaps the RFID chip inside the keyfob fell out, again you would need to buy a new fob head to be programmed to the car as my understanding is that the information from the tag for the key fob is programmed to the electronic box (not sure the correct name, yet) in the car. Good luck.

Everything works fine with starting and driving the car, but the doors will not lock or unlock remotely. The RFID module is still in place inside the key. -Shawn

Did you not use the car for 5 days and it went into sleep mode?

If he drove it is awake now. Probably new key head(s) and dealer programing are in your future. Total $$ ~$240

Try the reset procedure. Remove the new battery, then reinstall it upside down (reversed polarity) for about 10 seconds, remove the battery and reinstall it the correct way. Sometimes this works. It is worth a try.

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I'd be hesitant to do this, although Porsche likely has a diode in the ciructry for reverse polarity protection, it's never advisable to intentionally apply reverse voltage to an electronic circuit. That is unless Porsche has officially endorsed this "reset procedure" somewhere in their documentation, I couldn't say since I'm still waiting for my owner's manual that I ordered 2 weeks ago with no ETA specified......

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Actually looking at the design of the button cell what you are doing when you reverse the cell is to short the +/- contacts together. Possibly this could remove any stored charge in any capacitors in the circuit but I actually doubt it. I just tried this on one of my non-working (light flashes but doesn't unlock doors) and there was no change when I put the battery back in correctly.

Some people have reported that this has worked.

I gave the reverse polarity trick a try and it's still a no-go. Thanks for the suggestions. Any others? I'll try the dealer programming next. S.

Did you test the new battery to make sure it has voltage? Just a possibility.

The dealer will not be able to reprogram the key to the car without the key barcode. Also if you have any other working keys bring them so the dealer does not inadvertently delete a working one. Sunset Porsche (discounts mail order parts) has had the best price on new heads recently ~$125. You can also try EBay but be sure it includes the barcode or it is a $ paperweight. There is also a chance that one of the PC board traces or switch solder joints has cracked. Before you give up look at the board around the switches. If there is a crack you might be able to solder it. Some folks have had success with that.