Alarm, Keys, Remote
From Boxster Tech
Contents |
[edit] About the keys
When we talk about the Boxster's keys, it is important to distinguish the three main componenets:
1- the cut metal part that is inserted into the door or ignition
2- the remote control (transmitter)
3- the transponder (anti-theft device)
The cut metal part is obvious and can be removed from the key head.
The remote control sends a coded digital signal to the car. The car must be programmed to accept this code as valid in order to use it to lock/unlock the car and arm/disarm the alarm.
Each key has a unique passive transponder in it. If you take a key apart, it is clearly visible (see photo below). It is passive because it uses no electricity from the battery. Instead, there is a transmitter and a receiver near the ignition switch (where you stick the key in). This device transmits a signal which is "reflected" by the key with the key's identity.
So, the car needs to be programmed to recognize the key and that's what the dealer should be doing and hence the need to know the key's identity "code". I would also suppose that there must be some kind of security or anyone could steal your car and then program it to accept a new key. Just speculating here though.
[edit] Remote Key "Outside Lock-In Range"
I was looking for info in the shop manual and came across the section about programming the car to accept a new key etc. what is super interesting is that apparently, if you press your key more than 256 times and the car doesn't "hear" it, then the car will no longer recognize that key.
the explanation for this being that the key transmits rolling codes, i.e. the transmitted codes are different every time. so obviously, the car must know what code to expect next according to some secret algorithm. otherwise the concept wouldn't work.
so if the key gets too far ahead of the ecu, then they lose sync.
this may very well explain why some people's keys stop working all of a sudden. maybe the button got continually pressed while in a pants pocket or purse or something.
here's the text from the manual:
[edit] Repairing or Replacing the Ignition Switch
Porsche Boxster Ignition Switch Replacement
[edit] Extending the Range of your Remote Key
A weak battery in the key can cause a dramatic reduction in range for the remote key. Sometimes just replacing the battery can provide a good improvement in range. The battery is widely available at retail stores.
Further improvement can be done by working on the receiving antenna: procedure
Contributed by Stefan in Boston
[edit] More Info on Boxster keys
Everything you wanted to know about Boxster Keys
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