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Home >> Land Rover >> 2009 >> Range Rover (LM) V8-4.2L SC >> Repair and Diagnosis >> Accessories and Optional Equipment >> Radio, Stereo, and Compact Disc >> Description and Operation >> Part 1

Part 1



Audio System

AUDIO SYSTEM COMPONENT LOCATION







GENERAL
Two levels of the system are available and both systems use the Touch Screen Display (TSD) as their interface. One system is based around a Harman/Kardon DSP audio amplifier while the other is based around the Harman/Kardon Logic7 audio amplifier. The audio system has no option for a single CD (compact disc) or a cassette tape player.

It is also possible to specify extras to the audio system to extend its capabilities. These options include:
- Telephone
- Satellite navigation
- Television / Teletext
- Voice recognition system (navigation and telephone).
- Rear Seat Entertainment (RSE)

MOST
The components of the complete audio/infotainment system are all connected on the Media Orientated Systems Transport (MOST) ring. The MOST ring is a fibre optic communications bus for multi media applications. Sound and control information is passed around the MOST ring and can be picked up by any of the systems units. For example, sound information is sent from the CD (compact disc) autochanger along the MOST ring and is collected by the audio amplifier which then out puts the sound to the speakers.

MOST technology uses a plastic optical fibre which forms a network connecting the audio and multimedia system components. Each component in the ring is connected to the plastic optical fibre through a device known as a Fibre Optical Transceiver (FOT). Each FOT has two optical connections; one connection is sensitive to light and is the input and the second connection forms the light source and is the output. The system operates by connecting the output from one FOT to the input of another FOT.

The light signals are sent in one direction only and are formed in the following way:
- Electrical signals are converted into an electrical current
- The current then drives a LED (light emitting diode) in the FOT to produce a high intensity red light
- The LED (light emitting diode) transmits the light through a fibre optic cable
- A photo diode in the FOT at the opposite end of the fibre optic cable detects the light.

The following components are connected to the MOST ring:
- Integrated Head Unit (IHU)
- Touch Screen Display (TSD)
- SDARS receiver
- TV tuner
- Traffic Message Channel (TMC) module
- Amplifier
- Rear seat entertainment module
- Personal telephone integration module
- CD (compact disc) autochanger.

The IHU is the timing master for the MOST system. The IHU controls and manages the MOST ring and the system components. It is also responsible for the MOST security system. Each component in the MOST ring has a unique serial number. The component serial number is stored in a registry file in the instrument cluster. If any component serial number is not recognized, the entire audio system will not function.

A replaced component requires its serial number to programmed in the instrument cluster registry using Land Rover recommended diagnostic equipment. If the instrument cluster is replaced, the complete system will not function until the instrument cluster is programmed with the component serial numbers using Land Rover recommended diagnostic equipment.

MOST Diagnostics
A light box is used to diagnose the MOST system. The light box emits a visible, high intensity red light which can be connected into the ring at any point to test the ring integrity. The light box is used in conjunction with Land Rover recommended diagnostic equipment.

Disconnecting a MOST connector will reveal if the high intensity red light is visible. Do not view the red light directly. If a break occurs in the MOST ring fault codes are stored in the IHU which can be retrieved using Land Rover recommended diagnostic equipment.

INSTRUMENT CLUSTER GATEWAY FUNCTION
The instrument cluster incorporates a gateway function. The gateway function is the link between the vehicle bus systems and the audio system MOST ring. When the vehicle is unlocked, the instrument cluster receives a system 'wake-up' message on the CAN (controller area network) bus. This message is then passed to the integrated head unit (IHU) which then 'wakes-up' the MOST ring components by energizing the infotainment relay.

System Security
The gateway function stores a unique serial number for each component in the infotainment system. This new system, known as 'Security on MOST' replaces the radio codes used on previous audio systems.

During vehicle production, the serial number of each component is extracted from its memory and stored in the instrument cluster. At every subsequent ignition on cycle, the Integrated Head Unit (IHU) reads the serial number for each component and compares them to the stored serial numbers in the instrument cluster. If an incorrect code detected the MOST system will shut down and the infotainment system will not function.

If an infotainment component is replaced, Land Rover recommended diagnostic equipment will be required to disable the security on MOST feature. A file is downloaded which extracts the new serial number from the replacement component and records it in the instrument cluster. Land Rover recommended diagnostic equipment is used to re-enable the security on MOST feature and restore the system security.

INFOTAINMENT RELAY
An infotainment relay is located in the rear fusebox. The relay receives a permanent power supply from fusible link 8 in the passenger compartment fusebox. The relay coil is controlled by the IHU which provides a ground for the coil. When a vehicle unlocked signal is transmitted on the CAN (controller area network), the message is received by the IHU which provides a ground for the relay, closing the contacts and supplying power to the audio/infotainment system components. The IHU maintains the relay in an energized condition for a period of time after the ignition is switched off to allow time for the navigation computer to 'power down' and also to allow a faster system start-up if the system is required subsequently.

AUDIO SYSTEM
The Digital Signal Processor (DSP) audio system comprises:
- DSP amplifier
- Touch Screen Display (TSD)
- Integrated Head Unit (IHU)
- Six disc CD (compact disc) autochanger
- 11 Speakers

The Harman/Kardon Logic7 audio system comprises:
- Logic7 amplifier
- TSD
- IHU
- Six disc CD (compact disc) autochanger
- 14 Speakers

Touch Screen Display







The Touch Screen Display (TSD) forms the basis of the audio system. It communicates with the rest of the audio/infotainment system on the MOST ring and allows control of the audio system and other infotainment systems from a single point.

The TSD communicates with the Integrated Head Unit (IHU) on the MOST ring and provides the driver interface and driver display of the audio system. The TSD also provides driver display and control of the telephone, the rear view camera, the Venture Cam, the navigation system, the Traffic Message Channel and the rear seat entertainment.

The audio system and other systems are operated by a combination of the physical buttons located on each side of the screen and the 'virtual' buttons displayed on the touch screen. For clarification, the physical buttons are referred to as 'buttons' and the touch screen virtual buttons are referred to as 'icons'.

The TSD is a touch sensitive, 800 X 600 pixels LCD VGA screen which displays in a 15.9:1 format.

Care should be taken with the TSD to ensure its correct operation:
- The screen should be cleaned with a lightly, water moistened cloth. Do not use chemical agents or domestic products to clean the screen or any part of the surround.
- Only use your finger to operate the touch screen. Ensure you only use one finger to avoid incorrect entries.
- A short light press of the touch screen is sufficient. Excessive pressure can damage the screen.

Six connectors provide the interface between the TSD and the other system components.

On-Board Computer
The on-board computer functions can be accessed by from the TSD, by pressing the on-road information button on the LH (left-hand) side of the TSD. After pressing this button the last displayed screen in the on-road information selection appears in the TSD. The following screens are available in the on-road information screen:
- Fuel and temperature
- Speed
- Stopwatch
- Trip settings.

TSD Diagnostics

NOTE:
- Fault codes can also be retrieved using Land Rover recommended diagnostic tool.
- The navigation computer also has an on-board diagnostic mode which is accessible using the TSD.

The TSD has an on-board diagnostics capability to allow the functionality of the following to tested:
- touch screen icons
- Touch screen surrounding physical buttons
- Vehicle input signals
- Video inputs
- RGB color display
- Self test with fault codes displayed (if applicable)
- Configuration settings of the TSD
- Vehicle configuration
- MOST ring function

Use the following procedure to get access to the diagnostic screens.
- Insert the vehicle key in the ignition switch and turn to the ignition position II.
- Once the 'CAUTION' screen has been displayed, press the 'AGREE' virtual button in the bottom right hand corner of the TSD. The 'Home Menu' will be displayed.
- In a central position at the top of the TSD, press the screen and hold for 5 seconds, then release and press and hold the navigation physical button for 5 seconds and release. A 'Diag PIN Entry' box will appear.
- In the 'Diag PIN Entry' box, enter the diagnostic PIN entry code of '753' and press the 'OK' icon on the TSD. A 'Diagnostics Menu' screen will appear.
- The following selections can be made from the 'Diagnostics Menu' screen. Hard Key Test (physical buttons) Touch Switch Test (virtual icons) Vehicle signals Video Inputs Test RGB Color Test Self Test Configurations Vehicle Configurations MOST Test
- Once a screen display is complete, you can return to the previous menu screen by pressing the return icon in the top right hand corner of the TSD.
- Hard Key Test This screen displays a 'Hard Key Test Form' screen. The hard key test verifies the correct function of each of the physical buttons which surround the TSD. Pressing each button in turn will turn the applicable icon in the TSD green if the button is functioning correctly.
- TouchSwitch Test This screen displays the 'Touch Switch Test' screen which gives two selections; 'Start Calibration' and 'Touch Switch Check'. The 'Start Calibration' screen allows re-calibration of the screen. The touch screen co-ordinates can be aligned by pressing a series of on screen targets. To return to the 'Touch Switch Test' screen, press the 'Navigation' physical button. The 'Touch Switch Check' screen displays a blank screen. Touching the screen will display a series of co-ordinates for the area of the screen which has been touched. This can be used to check if an area of the screen has a fault.
- Vehicle Signals The vehicle signals screen displays inputs from other vehicle systems. The screen shows the 'real time' parameters and status of the following: Battery voltage Lights (on/off) Ambient light sensor voltage Backlight dimming duty (PWM (pulse width modulation) %) Graphic illumination dimming duty (PWM (pulse width modulation) %) Output audio allocation (AM (amplitude modulation) /FM (frequency modulation) tuner, CD (compact disc), Navigation, DVD, TV) PCB Temperature Speed inhibit (overspeed) (on/off) MOST FOT temperature (degrees C) Parking position (Park brake on/off) Backlight PWM (pulse width modulation) duty Beep volume Beep tone.
- Video Inputs Test The video inputs test screen allows the video inputs from the Venture Cam, Rear View Camera and the TV/DVD to be tested. Pressing the 'Companion Camera' icon enables the Venture Cam display. The Venture Cam must be removed from its docking station and switched on. The display can be switched between PAL and NTSC and also in two wide-screen formats and a normal view. Pressing the 'Rear View Camera' icon enables the rear view camera display. The display can be switched between PAL and NTSC and also in two widescreen formats and a normal view. Pressing the 'TV/DVD' icon enables the display from the TV tuner or the DVD player. The display can be switched between PAL and NTSC and also in two wide-screen formats and a normal view.
- RGB Color Test The RGB color test form screen allows the TSD color outputs to be tested. By pressing each color in turn, the whole screen is displayed in that color and the whole screen area can be checked for uniform color display. Pressing the screen a second time returns to the RGB color test form screen.
- Self Test The 'Self Test' screen displays the current ignition switch position, the battery output voltage and the diagnostic session. After a few seconds, the display will show any existing fault conditions in the form of a diagnostic trouble code and a brief description.
- Configurations The 'Configurations' screen allows the data for the TSD and also the Navigation Computer to be displayed. The display can be switched between the TSD and the Navigation computer by pressing the icon in the top left hand corner of the screen, which displays either 'Show MMM Information' (navigation computer) or 'Show HLDF Information' (TSD). Each screen shows the following information: Vehicle Type Serial Number Part Number / Parts Level Land Rover Software Version MOST SWDL Block Size Main CPU Software/Bootloader Versions Main CPU Application Version Sub CPU Software Version Private CAN (controller area network) Database Version
- Vehicle Configurations The 'Vehicle Configurations' screen has four separate screens which show information for each of the audio/navigation system components. Each screen can be displayed by pressing the 'Next' icon in the bottom right hand corner of the screen. A previous screen can be displayed by pressing the 'Prev.' icon adjacent to the 'Next' icon.
- MOST Test The 'Most Test Form' screen shows the information being passed on the MOST ring for each driver input. For example, when the screen is displayed, adjusting the volume control using the TSD rotary control or the steering wheel switches will show the MOST ring signals being transmitted. This can be repeated for each function to establish that the driver request is being transmitted on the MOST ring.
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