Special Vehicle Multifunction Control Unit (SVMCU (MSS)), Component Description - GF54.21-P-4010LFA

Model 222 with code Z07 (B7 armoring on special protection version) except code 965 (Taxi/rental car - electrical pre-installation) 

Location 

The special vehicle multifunction control unit (SVMCU) is behind the paneling on the right in the luggage compartment.

Task 

The special vehicle multifunction control unit (SVMCU [MSS]) has the following tasks:

• Reading in of sensors and signals 
• Evaluation of input factors 
• Output of signals 
• Actuation of components 

Reading in of sensors and signals 

The input factors are read in via the following connections:

• Direct line 
• Interior CAN (CAN B) 
• Multifunction CAN (CAN K) 

Direct line 

The signals from the following components are read via direct lines: With CODE Z22 (Panic alarm system (PAS)):

• PAS [GAS] and special signal system control unit (N26/12)
• Left footwell emergency alarm system button (S62/16)
• Right footwell emergency alarm system button (S62/17)
• Rear center console emergency alarm system button (S62/18)

With CODE Z21 (Fire extinguishing system) or CODE Z25 (Emergency fresh air system incl. device carrier plate):

• Fire extinguishing system and emergency fresh-air system control unit (N100)

Interior CAN 

The special vehicle multifunction control unit (SVMCU) reads in, among others, the following signals via the interior CAN:

• Status of the central locking (CL)
• Exterior lights status
• Outside temperature
• Engine speed

The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Multifunction CAN 

The signals are read in by the special vehicle multifunction control unit (SVMCU) via the multifunction CAN.

The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Evaluation of input factors 

The input factors that have been read in are evaluated by the integrated microprocessor whereupon the relevant signals are then issued.

Output of signals 

The signals are output via the following connections:

• Direct line 
• Interior CAN 
• Multifunction CAN 

Direct line 

The special vehicle multifunction control unit (SVMCU) sends signals to the following component via a direct line:

With CODE Z22 (Panic alarm system (PAS)):

• PAS [GAS] and special signal system control unit

Interior CAN 

The special vehicle multifunction control unit (SVMCU) sends, among others, the following signals via the interior CAN:

• Request for switching on "recirculated air"
• Request for alarm light functions (with CODE Z22 (Panic alarm system (PAS)))
• Request for alarm flashing (with CODE Z22 (Panic alarm system (PAS)))
• Request for closing CL (with CODE Z22 (Panic alarm system (PAS)))

The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Multifunction CAN 

The special vehicle multifunction control unit (SVMCU) sends, among others, the following signals via the multifunction CAN:

• Circuit status
• Wheel speed
• Diagnosis requests

The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Actuation of components 

On vehicles with CODE Z61 (Additional battery for emergency start), the special vehicle multifunction control unit (SVMCU) actuates the emergency start system relay (high current) (K53/12) directly.

Wiring diagram, special vehicle multifunction control unit (SVMCU [MSS])

PE54.21-P-2105-97SEB