Trip computer (TRIP), networking of components - GF54.50-P-0001-02T

Function survey 

The trip computer is integrated in the instrument cluster (A1). The instrument cluster (A1) is linked with:

• the engine compartment CAN and
• the interior compartment CAN

Data is exchanged with virtually all the control units over the two bus systems.

However, the instrument cluster (A1) does not act as an interface between the two data bus systems. This function is reserved for the central gateway control unit (N93).

This document lists the principal CAN messages for the functions of the instrument cluster (A1) including the trip computer.

The connections of the instrument cluster (A1) are described in the last part of this document.

The trip computer receives the following input signals:

• The wheel speeds over the engine compartment CAN from the ESP, SPS and BAS control module (N47-5)
• The consumption signal from the motor electronics control unit (N3/10) or CDI control unit (N3/9) via the engine compartment CAN
• The time over the interior compartment CAN from the audio gateway control module (N93/1), and this over MOST from the COMAND operating, display and control module (A40/3) in vehicles with COMAND operating, display and control module (A40/3)
• The states "Terminal 15" and "Key in ignition" over the interior compartment CAN from the EIS control module (N73)
• The actuation signals from the buttons on the multifunction steering wheel over the interior compartment CAN from the steering column module (N80)
• The fuel tank level over the interior compartment CAN from the rear SAM control module with fuse and relay module (N10/2)

CAN messages from the buttons on the multifunction steering wheel 

Since the buttons on the multifunction steering wheel each have several functions, the signals from these buttons must be processed accordingly:

• All the buttons in the left multifunction steering wheel button group (S110) and the right multifunction steering wheel button group (S111) are voltage-coded and are read by the steering column module (N80).
• The steering column module (N80) relays the relevant messages onto the interior compartment CAN.
• These CAN messages are received by the instrument cluster (A1).
• The instrument cluster (A1) interprets these messages in combination with the systems displayed in the multifunction display (A1p13) and passes on these interpreted messages again on the interior CAN.

Received messages for the multifunction display 

All signals for the messages in the multifunction display (A1p13) are received over the engine compartment CAN or interior CAN. The signal paths and further details on various messages can be read in the function descriptions of the systems in question.