I parked in my parking garage and locked the door manually. When I went back the door didn't unlock manually or with the key fob. The red security light is blinking, so I don't think it is a battery issue. Any ideas on how to get inside the car?

 

I just bought an 08 C4s, and am having the same problem with one of the keys.

If you get into the car and try to start it with that key, I bet nothing will happen, and the alarm will go off.

My light flashes too, so I assumed my battery is fine.

Ill be following this thread to see what other have to say

 

You say you locked the car with the key and now the key doesn't unlock it? Replace the battery in the key fob or try your other key fob.

 

In case you didn't already try this, you should relock the car with the key manually and see if the key will then unlock it. I hope this works for you, but I can't figure out why you couldn't unlock with the key in the lock...

 

How long ago did you lock it? after about a week it will go into hibernation mode. You then use the key to unlock it manually but disarm it afterwards.

 

Hmmm.... I bet that is what happened with mine. Thanks for the tip! Ill check it out.

 

If your car is in hibernation after 6 days of parking, lift handle on driver side and use the key fob to open the door and reactivate the system.
If you just use the key to open the door., you have 10 seconds to put key in ignition, otherwise the alarm will sound.
There are two codes, an electronic one to deactivate the alarm via the fob, if the door is opened with the key then the ignition lock will look for the passive transponder code in the key head.
Flashing LED does not mean the battery is OK in the key fob, the LED requires miniscule power to light.

 

My 997.2 has been hibernating for over a week BUT it's not locked since it's in my garage. If I just open the door and start the car, will that reactivate the key for the remote to work again? Or do I have to put the key in the door and go through the motion of locking and unlocking?

 

From the manual:

If the vehicle is not started or unlocked with the remote
control within 7 days, the remote control
standby function is switched off (to prevent discharging
of the vehicle battery).
1. In this case, unlock the driver’s door with the
key at the door lock.
Leave the door closed in order to prevent the
alarm system from being triggered.
2. Press button 1 on the remote control.
The remote control is now activated again.

Since your car wasn't locked with the remote, I don't think you have to do anything spcial.

 

Ok. Thanks!

 

My car has been hibernating for over a week, but unlocked. Today, I opened the door and braced myself for the alarm to go off. It didn't. Then, I started it up, drove a little bit, turned it off, got out and locked the door with the remote. No problem. So, I guess it reactivated the key when I put it in the ignition. This is just FYI for anyone who's car has been inactive but unlocked.

 

Leaving the car unlocked (even in a locked garage) will consume battery as certain systems do not shut down until you lock the car. It's a recommended habit to lock the car when not in use.

 

I keep my car locked in the garage and sometimes it goes beyond 7 days without starting or unlocking. It always unlocks with the remote - I wonder if having my car on a battery maintainer makes a difference?

 

I have a maintainer but still goes into hibernation
Wonder if it is in the settings set by PCM or Dealer ?