Instrument Panel, Gauges and Warning Indicators: Description and Operation
Instrument Panel
Instrument panel
New technology is used for the instrument panel: Black Panel. This is a panel coated on the rear side with a black foil. The Black Panel covers the entire area of the instrument panel (high version). The remaining area is designed in such a way that the symbols of the indicator lights are not visible when switched off. (Basic version). The two large accentuation rings for the speed reading and engine speed display are galvanized. The two small dial areas for the fuel gauge and engine oil temperature are also galvanized. When switched off, the active areas of the displays are not visible.
NOTICE: Changed fuel consumption indicator.
The fuel consumption indicator of the instrument cluster has been revised for model year 2012. After programming with ISTA/P 2.43.2 or higher, a yellow strip can be seen at the border. This is series status. Replacement of the
NOTICE: Additional fixed indicator lights.
In the basic version, there is additionally the indicator light LIM. This indicator light illuminates for pending information about Speed Limit Info (road sign recognition).
The instrument panel starts up gradually.
At the request of the transmission control unit, the engaged gear is displayed in the instrument panel.
Brief component description
The following components are described for the instrument panel:
TFT display
In the instrument panel, a horizontal 960 x 160 pixel TFT display is integrated under the round instrument. The large analogue round instruments are open in a downward direction. These round instruments are closed by graphics of the display.
Outside temperature sensor
The outside temperature sensor supplies the value for the ambient temperature to the instrument panel. The ambient temperature is shown on the liquid crystal display. Instrument resolution is 0.5 °C (1 °F). The value for ambient temperature is also made available to other control units via the K-CAN. The signal from the outside temperature sensor is digitalized in the instrument panel. A calculation model suppresses the effects of thermal radiation from the engine compartment on the signal. At higher driving speeds and lower engine temperatures the system selects lower damping action. The real outside temperature value can only be reliably expected starting at driving speed of about 80 km/h.
JBE: Junction Box Electronics
The power distribution box within the Junction Box Electronics module provides the instrument panel with the connection to Terminal 30F and Terminal 30B. In addition, the junction box electronics provide the instrument panel with various other required signals on the bus system (body CAN2 - central gateway module - powertrain CAN).
Fuel level sensor
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. The fuel level sensors are connected to the Junction Box Electronics (JBE). The signal is transmitted to the instrument panel on the K-CAN2.
NOTICE: Observe repair instructions.
The left-hand fuel level sensor cannot be replaced separately.
Coolant level switch
The coolant level switch sends a signal if the coolant level is too low (Reed contact). The information appears in the TFT display in the form of a Check Control message. The coolant level switch is connected to the Junction Box Electronics (JBE). The signal is transmitted to the instrument panel on the K-CAN.
Washer fluid level switch
The washer fluid level switch sends a signal when the washer fluid level is too low. The information appears in the TFT display in the form of a Check Control message. The washer fluid level switch is connected to the Junction Box Electronics (JBE). The signal is transmitted to the instrument panel on the K-CAN2.
Acoustic sensor
The acoustic sensor in the instrument panel (KOMBI) issues acoustic signals for the following functions:
- Turn indicators
- Hazard warning flashers
The volume varies as a function of vehicle speed.
On-board computer button
The on-board computer button is electrically connected to the steering column switch cluster (SZL). The signal is forwarded on the FlexRay to the central gateway module (ZGM). The instrument panel receives the signal on the PT-CAN from the central gateway module.
The on-board computer functions can be called up by briefly pressing the on-board computer button on the drop arm. Pressing the on-board computer button again displays the information in the following order:
- Remaining cruising range
- Average fuel consumption
- Average speed
- Distance (with route guidance activated)
- Estimated arrival time (with route guidance activated)
- Date
- Road sign recognition
System functions
The following system functions are described for the instrument panel:
- Operating readiness
- Operating voltage range
- Outside temperature value suppression
- Brightness control
- Set speed for the cruise control
- Redundant data storage
Operating readiness
Operational status (operating readiness) depends on the terminal.
- Terminal 30B (basic operation) and Terminal 30F (fault)
The instrument cluster receives power from Terminal 30B and 30F via the junction box. The terminal status (Terminal R or Terminal 15) is made available to the instrument panel via the bus system. With terminal 30 (terminal R Off), the instrument panel is in the standby mode. Pressing the reset button wakens the instrument panel to display the following: Odometer, time display, ambient temperature, fuel level (can be encoded). The display goes out after 25 seconds.
- Terminal R
With terminal R On, the following are evaluated: Turn signal/high beam switch and fuel level sensor. The time and ambient temperature appear in the TFT display. The on-board computer functions can be started using the on-board computer button (display unlimited in time).
Terminal R is reached automatically once the engine has been stopped.
- Terminal 15
When terminal 15 is switched ON, a pre-drive check is carried out on the permanent indicator and warning lights.
- Terminal 50 (starter motor)
During the engine start, the vehicle voltage can fall to such a degree that the internal voltage supply (6 Volts) can no longer be maintained. In this case, no analogue signals can be evaluated. No storage processes are run (in the EEPROM) either.
Operating voltage range
The operating voltage range is from 9 to 16 Volts. At a voltage below 7.5 Volts, undervoltage is detected. At a voltage above 16 Volts, no analogue inputs are evaluated.
Outside temperature value suppression
The computation model in the instrument panel compensates for effect that the residual heat from the engine compartment has on the ambient temperature signal. The increase in temperature is delayed. The input variables for the calculation model are:
- Driving speed
- Coolant temperature
- Status engine on/off
- Ambient temperature
A drop in the ambient temperature is adopted and not damped. The engine and the body cannot be colder than the ambient temperature.
NOTICE: Under certain circumstances, an incorrect display of the ambient temperature is physically unavoidable.
Under certain driving conditions, the display deviates from the real value due to damping action. In the event of a customer complaint, this behavior must be explained as the state of the art.
Example for outside temperature compensation:
Motorway driving followed by urban traffic, then stationary traffic
Brightness control
Due to the Black Panel technology, the instrument panel is always illuminated as of terminal R. The status of the vehicle lights and the ambient brightness determine the switch between daytime and night-time illumination. A phototransistor is installed in the instrument panel to calculate the necessary brightness (display, indicator and warning lights, scales, needles).
The brightness value calculated in the instrument panel is transmitted to the bus system (e.g., for the Central Information Display). Dimming can be set individually using the rheostat wheel on the light switch. When the vehicle lights are switched on, these individual settings and the phototransistor are used to control the dimming. When the vehicle lights are switched off, the dimming is only controlled by the phototransistor (display brightness according to ambient brightness).
Set speed of the cruise control
The set speed of the cruise control is transferred by the control unit for Integrated Chassis Management (ICM) on the bus system. Cruise control is activated via the steering column switch cluster (SZL). The set speed is transferred and displayed with a resolution of 1 kph. The set speed is indicated by a 2 colour marking (needle):
- Green: Cruise control active
- Orange: Cruise control not active
Notes for Service department
General notes
Instrument cluster test functions
The test functions are displayed in the TFT display of the instrument panel. The test functions are used in service to check the encoding. The test functions are also an aid to troubleshooting without the diagnosis system.
Starting the test functions
- Precondition: Terminal R ON, vehicle stationary, engine switched off
- Hold down the reset button in the instrument panel for 15 seconds
Locking and unlocking test functions (test function 19)
Only the first two test functions are freely accessible. As of the 3rd test function, all other test functions are locked. Unlocking is only possible using test function 19. The test functions are unlocked by entering the total of the vehicle identification number.
Terminating the test function
- Terminal change
- Press the reset button for longer than 5 seconds
- Calling up Test function 21
National-market versions
The instrument panel is available in various national-market versions.
We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.