Instrument cluster (IC), networking of components - GF54.30-P-0002-06B

The instrument cluster (A1) is connected to the CAN/engine compartment and  to other control modules, switches etc. via discrete lines.

In addition there is a CAN data bus which exchanges information between the instrument cluster (A1) and radio (A2) or COMAND operating, display and control module (A40/3). It is abbreviated to "CAN (A1 - A2, A40/3)"  .

The key CAN messages  are listed here for the functions of the instrument cluster (A1) including the trip computer and ASSYST.

The key discrete connections  of the instrument cluster (A1) are described in the final section of this document.

Receive messages for display instruments and internal further processing: 

• The four wheel speeds  come from the traction systems control module (N47) via the CAN/engine compartment
• The < f >engine speed signal< f > comes from the injection system control module (N3) via the CAN/engine compartment
• Shift range, selector lever position, drive program  come from the ETC control module (N15/3) via the CAN/engine compartment
• The coolant temperature  comes from the injection system control module (N3) via the CAN/engine compartment
• The fuel consumption signal  comes from the injection system control module (N3) via the CAN/engine compartment
• The oil level  (not for vehicles with engine 111) comes from the injection system control module (N3) via the CAN/engine compartment
• The oil temperature  (not for vehicles with engine 111) comes from the injection system control module (N3) via the CAN/ engine compartment
• On vehicles with COMAND: The time  comes via CAN (A1 - A40/3) 
• Signals from the multifunction steering wheel buttons:  see separate document.

Signals for indicator and warning lamps: 

• The signal for the left and right turn signal indicator lamps  (Ale1, Ale2)) comes from the light module (N7-1) via a discrete line for all types of turn signal  .
• The signal for the high beam indicator lamp  (A1e3) comes from the light module (N7-1) via a discrete line.
• The signal for the low brake fluid level/parking brake indicator lamp  (A1e7) comes from the traction systems control module (N47) via the CAN/engine compartment for the parking brake indicator and for low brake fluid level from brake fluid level switch S11 via a discrete line.
• The signal for the preglow indicator lamp  (A1e16) comes from the injection system control module (N3) via the CAN/engine compartment.
• The signal for the ESP warning lamp  (A1e41) comes from the traction systems control module (N47) via the CAN/engine compartment.
• The signal for the seat belt reminder lamp  (A1e9) comes from the seat belt buckle switch via discrete lines.
• The signal for the engine diagnosis malfunction indicator lamp  or "CHECK ENGINE" MIL (A1e58 or A1e26) comes from the injection system control module (N3) via the CAN/engine compartment.
• The airbag indicator and warning lamp  (A1e15) is actuated directly via a discrete line.

Signals and receive messages for the multifunction display (A1p13): 

• The signals for the messages in the multifunction display (A1p13) come via the CAN/engine compartment or discrete lines. The signal paths and further details on the individual messages can be found in the function descriptions of the particular systems  .

The most important send messages  from the instrument cluster (A1) to the CAN/engine compartment  are:

• Outside temperature signal 
• Fuel tank level 
• Terminal 58 d 
• Terminal 61 e 
• Engine shut-off time 
• Winter tires-maximum speed 

The most important send messages  of instrument cluster (A1) to the CAN (A1 - A2, A40/3)  :

• Button status of multifunction steering wheel,
• Button status of language control system (LCS) switch (S93/2)

Discrete lines go from the instrument cluster 

• to the brake fluid level switch (S11),
• to the seat belt buckle switch,
• to the light module (N7-1)
• to the multifunction steering wheel,
• to the SRS control module (N2/7)
• to the operating system for the center and side air outlet flap control module (TAC, AAC) (N18/2),
• to search illumination consumers
• to the engine coolant level indicator switch (S41) and windshield washer fluid level indicator switch (S42),
• to the language control system (LCS) switch (S93/2)
• to the generator (G2),
• to the DI control module (N73),
• for the voltage supply.
• to the hydraulic fluid level switch (S77/2)