I recently found another key for my 2004 C4S. The battery in the fob was dead. I replaced the battery in the key fob. It lights up when you press the button, but the key will not operate the door locks, frunk, or start the ignition. I read in the manual to leave the key in the ignition for two minutes, turned to the "0" position. Still did not work. Any help would be appreciated, please advise. Thanks

 

Was the key from your car originally?

 

Yes, as far as I can tell. It has all the same cuts, fits the ignition and I can turn the ignition to the start position. Thanks

 

Bad transponder. Try swapping the transponder from your good key to the bad one.

Either transponder broke or someone put a blade that fits your car into another fob. To program the fob you need the 20 digit key.

 

Thanks, I just tried the swap and got the same results. Guess I will have to make a trip over to the dealer tomorrow. Thanks for your help though, I appreciate it.

 

The porsche system is broken down to two parts. One is the "pill" that actually looks like a small capsule that's embedded in the key fob. This can be transferred to any other fob. This pill is needed to actually start the car.

The fob itself is only needed to operate the locking/arming/panic functions. Both are programmed to the alarm brain module. If you've never used the second fob that came with your car, it could've been a used one that was never properly programmed by the previous owner.

You can easily test whether the key fob is paired to your alarm with a pst2 or Piwis.

 

Thanks to all that responded. After digging deeper on this forum I found the answer and want to post it for anyone else with this issue.

1. I took the key, put it in the ignition and turned the car on to the start position.

2. I then pressed the button on the key fob for 10 seconds.

3. Then I turned the ignition back to off.

4. I took the key , put it back in ignition and the car started. It will still not unlock the doors, etc. but the car starts and I can unlock it with the key, so I'm good with that because it's a back up key anyway.

Hope this helps someone out, as I was not looking forward to going to the dealer to get a 20 digit code and all that, and who know what I would have paid. I want to thank you all for the camaraderie, mods, updates, pictures, encouragement and helpful hints to do all these small but meaningful projects on my car. Cheers!

 

[QUOTE=bernard.barbour;4071296] I'm good with that because it's a back up key anyway. /QUOTE]

Be careful with that attitude. If you have a problem, or lose, your primary key - and your "backup" is not fully functional, you could end up having to buy two new keys + programming. I would (and have) replace the "backup" and make sure you always have to working keys. You never know when .............