Land Rover Discovery: Instrument Cluster / Description and Operation

COMPONENT LOCATION

1. Head Up Display (HUD) Control Module
2. HUD Cooling Fan Motor
3. Head Up Display Cooling Fan Control Module (HUDCFCM)
4. Instrument Cluster (IC)

OVERVIEW

INSTRUMENT CLUSTER

The Instrument Cluster (IC) comprises of two analogue gauges for the speedometer, a tachometer and a 5 inch Thin Film Transistor (TFT) message center for driver information.

The analogue gauges are electronically driven using vehicle speed information from the Anti-Lock Brake System (ABS) control module for the speedometer and engine speed signals from the Engine Control Module (ECM) for the tachometer. The information is passed to the IC from the modules on the High Speed (HS) Controller Area Network (CAN) powertrain and chassis busses.

The speedometer is located on the left side of the instrument cluster and is available in three market variants:

• Major scale MPH (miles per hour) UK (United Kingdom) Diesel and Petrol.
• Major scale MPH US (United States) Petrol.
• Major scale KM/H ROW (Rest of World) Diesel and Petrol.

The secondary speedometer is a digital display in the TFT message center.

In most markets, the displayed units shown can be toggled via the "units" option in the trip computer menu. The tachometer is located on the right side of the instrument cluster.

The tachometer is located on the right side of the IC and is available in two RPM (revolution per minute) displays: one for petrol models and one for diesel models.

• Petrol models with a maximum engine speed of 8000 RPM.
• Diesel models with a maximum engine of 6000 RPM.

The TFT message center displays vehicle related information to the driver, for example; engine temperature, fuel level, gear position, Head Up Display (HUD) information, Terrain Response Auto2, speed control and Hill Descent Control (HDC).

Driver information is also displayed, for example; navigation turn-by-turn information, voice control, trip computer information and basic audio details.

The gauges are illuminated in a pure white color, but change to a red color when dynamic mode is selected.

The instrument cluster features a number of warning indicators. The warning indicators illuminate in one of four colors which indicate at the level of importance of the warning as follows:

• Red = Warning.
• Amber = Caution.
• Green = System operative.
• Blue = Headlamp high beam operative.

A vehicle information and settings menu is available to allow the driver to select certain features and functions of the vehicle, IC, trip computer and service information and change them to their personal preference. A menu control 'joy pad' is located on the right steering wheel and allows selection of the displayed functions and navigation of the menus. When selected, the menu is displayed in the TFT message center.

HEAD UP DISPLAY

The Head Up Display (HUD) is a transparent display that presents data without the driver requiring to look away from their viewpoint.

A virtual image is displayed on the windscreen which appears at a distance of approximately 2 meters, giving the impression that the image appears around the end of the bonnet.

This function is designed to provide an increase in safety and convenience by maximizing eyes on the road time.

The HUD is designed to work with a specially designed windscreen, which is formed to prevent double images and achieve the best display performance.

When selected the HUD feature projects the following driver information display onto the inside of the windscreen:

• Vehicle speed.
• Traffic Sign Recognition (TSR) and Identified speed limits.
• Gear selection.
• Navigation instructions.
• Cruise control/Automatic Speed Limiter (ASL) active symbol.
• Cruise control/Automatic Speed Limiter (ASL) set speed symbol.
• Follow mode active symbol.

Instrument Cluster / Description

WARNING INDICATORS

1. Side Lamps 'ON' Warning Indicator (this is also used to inform driver the headlamps on)
2. Anti-lock Brake System (ABS) Warning Indicator
3. Adaptive Front Lighting System (AFS) Warning Indicator
4. Hill Descent Control (HDC) Warning Indicator (not applicable to front wheel drive vehicles)
5. High Beam 'ON' Warning Indicator
6. Message Center
7. Tire Pressure Monitoring System (TPMS) Warning Indicator
8. Seatbelt Warning Indicator
9. Airbag/Supplementary Restraint System (SRS) Warning Indicator
10. Engine Malfunction Indicator Lamp (MIL)
11. Rear Fog Lamps Active Warning Indicator
12. Trailer Turn Signal Warning Indicators
13. Dynamic Stability Control (DSC) Warning Indicator
14. Dynamic Stability Control (DSC) 'OFF' Warning Indicator
15. Right Turn Signal
16. Front Fog Lamps Active Warning Indicator
17. Left Turn Signal Indicator
18. Alarm System Light Emitting Diode (LED)
19. Low Brake Fluid or Electronic Brake Distribution Fault Warning Indicator (red) (symbol shown as 'BRAKE' in NAS markets)
20. Low Brake Pads or Emergency Brake Assist (EBA) Fault Warning Indicator (amber) (Symbol shown as 'BRAKE' in NAS markets)
21. Cruise Control Active Warning Indicator
22. Auto High Beam (AHB) Enabled Warning Indicator

The warning indicators are mainly located in 3 groups; one in the speedometer display, one in the tachometer display and one group in a central position at the top of the TFT message center. The warning indicators can be split into two groups; self controlled and externally controlled.

Self controlled warning indicators are dependant on software logic within the instrument cluster for activation. The instrument cluster software controls the warning indicator check illumination at ignition on and all indicators whose operation is controlled by the instrument cluster; the low fuel level warning indicator for example.

Externally controlled indicators are supplied with current from another system control module or illuminated by the instrument cluster on receipt of a bus message from another system control module. Some indicators are activated by an external system control module but the instrument cluster contains the control logic.

ANALOGUE INSTRUMENTS

The analogue speedometer and tachometer are located in the instrument cluster. The speedometer and tachometer are each driven by an electronic stepper motor. The characteristics of this type of motor produce damping of the pointer needle. Both of the gauges return to their respective zero positions when the ignition is switched off.

The speedometer is driven by square wave signals derived from the wheel speed sensors and the Anti-lock Brake System (ABS) control module. The signal is received via the Engine Control Module (ECM) on the High Speed (HS) Controller Area Network (CAN) chassis bus.

The tachometer is driven by an engine speed signal transmitted on the HS CAN powertrain bus from the ECM. The signal is derived from the Crankshaft Position (CKP) sensor.

MESSAGE CENTER

For additional information, refer to: Information and Message Center (413- 08 Information and Message Center, Description and Operation).

HEAD UP DISPLAY (HUD) CONTROL MODULE

1. Speed Control/Adaptive Speed Control Display
2. Speed Control/Adaptive Speed Control Set Speed
3. Follow Mode Warning Indicator
4. Gear Position Display
5. Navigation Turn-By-Turn Display
6. Current Vehicle Speed
7. Traffic Sign Recognition (TSR) Display
8. Head Up Display (HUD) Control Module

The Head Up Display (HUD) control module is located inside the instrument panel behind the Instrument Cluster (IC).

The HUD control module receives a permanent battery voltage supply via the Rear Junction Box (RJB). A Medium Speed (MS) Controller Area Network (CAN) comfort bus allows for the HUD control module to communicate with other modules such as Head Up Display Cooling Fan Control Module (HUDCFCM) and Instrument Cluster (IC).

The Head Up Display (HUD) uses laser beams within the module to provide the light source, projecting images stored within the laser diode block, via a collimating lens, onto a Liquid Crystal On Silicone (LCOS) surface, with which the beams have a phase relationship. The light is reflected off through a fourier lens and a series of 'fold' mirrors to create an image on a rotating diffuser (this reduces speckle effects of the laser light). The light is magnified and distorted, in cohesion with the windscreen curvature, and passed across two further freeform curved mirrors, forming the virtual image seen by the driver.

HEAD UP DISPLAY COOLING FAN CONTROL MODULE (HUDCFCM)

The Head Up Display Cooling Fan Control Module (HUDCFCM) is located inside the instrument panel.

The HUDCFCM is powered by the Rear Junction Box (RJB).

Information can be sent or received via the Medium Speed (MS) Controller Area Network (CAN) comfort bus.

The HUDCFCM controls the Head Up Display (HUD) cooling fan by using a Pulse Width Modulation (PWM) signal.

HEAD UP DISPLAY (HUD) COOLING FAN MOTOR

The Head Up Display (HUD) cooling fan is located inside the instrument panel.

The HUD cooling fan is powered by the Rear Junction Box (RJB).

The HUD cooling fan is controlled by a Pulse Width Modulation (PWM) from the Head Up Display Cooling Fan Control Module (HUDCFCM).

The HUD cooling fan has a built in sensor to control temperature, so that the motor does not exceed it's operating temperature.

Instrument Cluster (G1791762) Removal and InstallationInstrument Cluster / Operation

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