Central locking control with mechanical key, function - GF80.20-P-2004T

Model 211.0/1 

Fig 1: Identifying Mechanical Key Release Pushbutton And Mechanical Key

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The driver's door and the trunk lid can be locked or unlocked manually with the mechanical key (7). This is done by purely mechanical means, without changing  the status of the central locking.

Vehicles with code (551a) Anti-theft alarm (ATA)  The anti-theft alarm is not deactivated in this case. Insert main or emergency key into EIS control module to switch off the starting alarm.