So I just picked up this 06 911 C2S and 2 weeks in I’m having weird alarm problems. Basically when I get in proximity to the car instead of the alarm disarming once and unlocking the car, it does it over and over again until I start the car. Then after driving the car and I pull the key out of the ignition, the alarm arming horn beep goes nuts and keeps arming and disarming until I get out of range with the key. The frunk also pops occasionally.

I pulled codes for the car and it’s showing

8041 Key Switch Stuck
8004 Terminal 50
C140 Communication Instrument Cluster
C131 Communication Gateway Control Unit

Ive searched quite a bit and can’t find anything

Battery is brand new and a factory AGM VAG battery so no concerns there. Battery testing turned up nothing.

Any ideas would be greatly appreciated!

 

Still looking for answers. Lots of searching had turned up very little.

 

Does it do the same with your other key? Maybe your key buttons have gone bad and are sending the transmitter signals over and over. If not, then sounds like the alarm module that receives the signals is bad.

 

The remote portion is not working despite the key looking pristine, even with a brand new battery.

When I unlock the car manually with the other key, the door will unlock, but the alarm goes off until I start the car.

I was thinking it was they key and will try to swap the pill and battery to the newer looking key and see what happens.

 

This is what I would do to check if the 1st key was in fact sending continuous signal to the car's security receiver.
1. Get your 2nd key to start the car using what ever method to get it up to this point.
2. While the car is idling with the 2nd key, take the battery out of your 1st key.
3. Shut the engine off, get out, lock the car normally, unlock it, get in the car and restart. If this solves your problem, then the 1st key was the problem.
4. If the problem continues, then the Theft/alarm sensor/module may be the culprit. I you change this part, it then will require programming from the dealer before it will work with your vehicle

 

Thanks for the reply. I did a variation of your suggested test and the conclusion was that if the battery was removed, the car stopped arming and disarming itself all on its own.

I ended up taking both keys to a local locksmith and determined that the contacts were not making a good connection to the battery on the one key and the other key wasn’t making a connection at all. Additionally, the keys appeared to have taken on water at some point and had some corrosion on the circuit board itself.

At this time I’m going to clean up all of the connections and the circuit boards and hopefully that will clear up the issues. I’ll report back once I’ve confirmed.