Volkswagen Key Fob Immobiliser and Transmitter

Replacement Switchblade Key Fobs for Mark V Volkswagen Golf’s, Passats, Jetta’s, Bettles and other models can cost up to AUD$500 to replace from the dealer, cheaper options are available including ebay, this guide doesn’t attempt to cover the process of procuring parts but goes through the steps involved. Sites like eBay and so forth should be used to obtain parts.

There are 3 parts to the switchblade remote (2 from a parts perspective).

These are the Transmitter and the Switchblade with contains the Transponder.

1K0 959 753 (see below) – Transmitter (top half)
1T0 837 246 INB – Switchblade and Transponder (bottom half)


The switchblade is the part of the key that houses the pop out keypart, this can be cut by many locksmiths or can be ordered through the dealer where it is laser cut in Germany.


The transponder is located in the switchblade section of the keyblade section and is coated with glass, this is removable and can be transplanted to a new key.  When the key is turned in the ignition a small emmitter powers up the transponder and reads the code from the transponder, if this code matches what the car expects the car starts and a new code is written to the transponder and car for the next time the transponder is used.

If the car does not recognise the transponder or none is detected the car will still start but stop after 1-2 seconds and display either a symbol of a key or the message on the MFD “Immobiliser Active”.

There are three versions of immobiliser used in the Mark V, early models used the Immo-1 and Immo-2 systems and Immo-3 is the current system. Using Vagcom/VCDS you can determine the system that you have by opening Controller 17 or Controll er 25 if it will allow you and look in the first extra field. “Immo-ID VWZ…..” means you have Immo-1 or Immo-2, if you have ” VWZ… VWZ…” where the first number is your VIN and the second is your immobiliser ID you have a Immo-3.

A new transponder can only be paired to a car using the Secret Key Code (SKC), this used to be freely available via the dealer however on the 1st of April 2005 Volkswagen changed to a new system (GeKo) that required a dealer scan tool (VAS 5052) to be connected to the car and it connects to the Volkswagen factory in Germany (there is one in the USA if you are in that country). The SKC used to be 4 digits and provided with the car prior to 2002, in late 2002 Volkswagen changed to a 7 digit code based on the 14 digit immobiliser ID along with your VIN number. With this 7 digit code you could add new transponders to the immobiliser however without knowing your SKC you have to rely on the dealership to do this for you. There are a few products available that will read the SKC from your car (see software below).

If you purchase the transponder seperately there are 4 variations (I’m pretty sure that VW dealers can’t sell these seperately)

  • 7M0 837 246 A
  • 7M0 837 246 B
  • 7M0 837 246 C
  • 7M0 837 246 D


There are a number of different transmitters for the Golf 5, you need to purchase one that matches the frequency of the vehicle.

HLO 1K0 959 753 A – 434MHz
HLO 1K0 959 753 B – 315MHz
HLO 1K0 959 753 C – 315MHz
HLO 1K0 959 753 D – 315MHz
HLO 1K0 959 753 G – 434MHz

To program the transmitter to the car is simple

  • Put your original key in the ignition and turn to the on position
  • Close the door and place the new key in the drivers door lock and turn the key to lock the doors and release so that it returns to the same positon where you inserted it
  • Hold down the lock button for a few seconds (if the alarm chirp is enabled it will chirp)
  • Press the unlock button, open the door and remove the original key

The transmitter should now operate correctly.


Software is available to read the SKC from all Volkswagens

VAGTACHO (Vagtacho.exe)

Immobiliser Login Reader


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