Brief description of components

The instrument cluster receives input signals from the following components:

• Outside temperature sensor 

  The outside temperature sensor supplies the value for the temperature outside the car to the instrument cluster. The outside temperature is shown on the liquid-crystal display. Instrument resolution is 0.5 °C (1 °F). The value for outside temperature is also made available to other control units via the K-CAN.

• Fuel-level sensors, left and right 

  The fuel tank contains two fuel-level sensors. Each fuel-level sensor sends a signal indicating the amount of fuel in the tank. A value is obtained by adding the two signals.

Below, the responsible control units are listed which have a permanent indicator lamp. These control units communicate with the instrument cluster control unit via the PT-CAN and K-CAN.

• DSC: Dynamic Stability Control 

  An active regulation sequence or a fault in the DSC will be indicated by the corresponding indicator and warning light (ABS, DSC or DTC).

  The brake pad wear sensors are also connected to the DSC control unit. The general brake warning light is actuated if the brake pads wear to the permissible limit. Front and rear brake pad wear is a CBS maintenance operation (sensor-based).

  Similarly, the Run Flat Indicator is integrated in the DSC. The RPA records the wheel speeds using the wheel-speed sensors. The RPA compares the speeds of the individual wheels and computes an average speed. In this way the RPA is able to detect a loss of tire pressure. The RPA fault status is displayed by the RPA indicator and warning light.

• ACC: Active Cruise Control - E6x only 

  There are an indicator and warning lights in the instrument cluster for Active Cruise Control (ACC). They indicate: Object detected or driver override, distance levels 1 to 4.

• AL: active front steering 

  A fault in the active front steering system is indicated by the corresponding indicator and warning light being actuated.

• DME or DDE: digital engine electronics or digital diesel electronics 

  The appropriate indicator and warning light is activated to indicate a fault in the DME or DDE.

  Engine oil is a CBS maintenance operation.

• ACSM: Crash safety module 

  The appropriate indicator and warning light is activated to indicate a fault in the passive safety system (airbag).

  The ACSM (= Advanced Crash Safety Module) is connected to the K-CAN.

  • E6x before 09/2005

  These vehicles have a safety and gateway module (SGM) that is connected to the byteflight  .

• LM: light module - E6x only 

  When the vehicle lighting (e.g. turn signals, main-beam headlights) is actuated, the light module (LM) sends the information to the instrument cluster and the corresponding indicator and warning lights are actuated.

• FRM: footwell module - E70 only 

  When the vehicle lighting (e.g. turn signals, main-beam headlights) is actuated, the footwell module (FRM) sends the information to the instrument cluster and the corresponding indicator and warning lights are actuated.

• EMF: electromechanical parking brake - E70 only 

  The electromechanical parking brake is a parking brake.

  In the event of a failure or malfunction in the EMF, the warning and indicator lamp for the EMF will light up.

  When the Automatic Hold button is pressed, "AUTO H" appears under the parking brake indicator lamp.

• TLC: track lane control - only E6x from 03/2007 

  TLC (also Time to Line Crossing) warns the driver before he leaves his lane. The display that track lane control is switched on or off appears on the instrument cluster and optionally on the head-up display.

Other control units communicate via the bus to send messages (check-control messages) to the instrument cluster. The instrument cluster emits these Check-Control messages via symbols in the LCD display.

The following control units remain important for the function of the instrument cluster:

• Headset and Central Information Display 

  For the instrument cluster, the headset (M-ASK, CHAMP, CCC) serves as the interface to the Central Information Display (CID). The CID displays detailed texts concerning Check-Control messages and information about CBS and other on-board computer functions. The CID also enables the driver to change the units of measurement (e.g. Celsius to Fahrenheit, and vice versa) for the instrument cluster.

  Moreover, the headset establishes a telephone connection when a CBS maintenance operation is due (= TeleService). This is achieved by sending a message to the telephone control unit via the MOST.

• EGS: Electronic transmission control 

  The EGS control unit supplies the signal for the gear engaged to the instrument cluster. The selected gear is shown in the selector-lever and shift indicator in the LCD display.

  • E6x from 03/2007 and E70

  The gear is selected with the gear selector switch (GWS). The GWS is a control unit in its own right on the PT-CAN.

• Car access system 

  The CAS control unit serves for redundant data storage. The following are stored in the CAS control unit (redundantly to the instrument cluster):

  • Vehicle identification number
  • Odometer status
  • CBS data
• Integrated automatic heating/air-conditioning system - only E6x up to 03/2007 

  The IHKA calculates the condition of the microfilter. The condition of the microfilter is CBS maintenance operation.

The instrument cluster internally controls the following instruments and indicators:

• Analogue instruments and moving-disc indicators 

  The instrument cluster incorporates a number of instruments that operate with step motors, namely:

  • Speedometer
  • Revolution counter
  • Fuel gauge
  • Fuel consumption indicator (E60, E61, E70)
  • Engine oil temperature (E63/E64)
  • Moving-disc instrument for the speed setting of the cruise control system
  • Moving-disc instrument for variable engine speed warning zone (currently only M-Technology)
• Indicator and warning lights: 

  The single-color indicator and warning lights that are required by law at the top, centered between the two large analogue instruments (exception: turn signal indicator lights at sides).

  The most important indicator and warning lights briefly light up during the pre-drive-check when terminal 15 is switched ON. The indicator warning lights and symbols are illuminated by LEDs which are soldered into place.

• Liquid-crystal display 

  The liquid-crystal display is centered at the bottom between the two large analogue instruments. The liquid-crystal display is divided into two zones. The top zone shows information such as the time and date and the outside temperature. In addition, Check-Control messages appear by means of a symbol in the top area. The bottom zone displays information concerning the on-board computer functions, for example, and the drive range currently selected for the automatic transmission. The shift point indicator (E60, E61) is also in he lower area.

  The LCD display is activated when terminal R is switched ON.

• Acoustic generator 

  Acoustic warnings are issued in support of the check-control messages. The instrument cluster controls these warnings by means of the K-CAN. The headset (M-ASK, CHAMP, CCC) outputs acoustic warnings via the loudspeakers.

  An additional loudspeaker in the instrument cluster issues the following acoustic warnings:

  • Flash
  • Warning flash