Keyless Entry: Service and Repair

Replacement of infrared remote central locking components (vehicles with stage 2 drive authorization system)
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The infrared remote central locking control module and engine control module are permanently assigned to one another with an identification code. For this reason the infrared portion of the locking system number must remain in the vehicle for the entire vehicle service life. This means that it is only possible to change the mechanical portion of the locking system number as well as the check digit.






Locking system number format

This means that when a remote control key or mechanical key is lost:
- The IRCL portion of the locking system number remains unchanged lost keys can be invalidated by desynchronization of the control module or by inhibiting the associated remote control key revocably or irrevocably (only on specific request of customer).
- Changing mechanical portion of locking system number install mechanical locks with new locking system number all around. A sticker with the 8-digit locking system number indicating the VIN must also be sent to department VP/MAM2, Mercedes-Benz AG; D-70322 Stuttgart.

This means that when the IRCL control module is defective:
- The IRCL portion of the locking system number remains unchanged -> install new control module with same locking system number.

This means that when one of the mechanical lock components is defective:
- The locking system number is maintained -> replace lock component using the same locking system number.







Inhibiting Infrared remote control keys revocably or Irrevocably (vehicles with stage 2 drive authorization system)

As of introduction of the IRCL control modules with part no. 210 820 27 26 / 28 26 as of approx. 09/95 the infrared remote control keys can be inhibited revocably with the hand-held tester. Certain infrared remote control keys can be inhibited with the hand-held tester with menu guidance. Certain remote control keys can be revocably inhibited and reenabled with the hand-held tester module 06/95.

As of introduction of the stage 2 drive authorization system infrared remote control keys can be inhibited Irrevocably with the hand-held tester. Certain remote control keys can be inhibited with the hand-held tester with menu guidance.
A certain remote control key should be inhibited irrevocably only when the key in question has been lost and this is requested specifically by the customer.

All vehicles are shipped from the factory with remote control keys "1" and "2". The spare infrared remote control key supplied as of approx. 05/95 will be assigned the number "3". Moreover, any sequentially numbered remote control keys purchased later must be taken into consideration. The remote control keys still present can be recognized on the basis of the numbers embossed on the remote control key housing. Remove the battery compartment cover on the remote control key to read off the identification numbers.
The number of the lost remote control key to be inhibited can be determined in this manner.