L322 Range Rover System Description and Operation
INSTRUMENTS
DESCRIPTION AND OPERATION
88-21
3 To set the sequence, select the required functions in order required. If no functions are selected and the 'SET'
button is pressed, all computer functions are selected and displayed in their standard sequence.
4 When the selections have been made, press the 'SET' button. The selected functions are stored in their selected
order in the instrument pack RAM. The instrument pack message centre displays the first selected function.
Bus Systems
The instrument pack has two controlling microprocessors which process software information and control input and
output data for the instrument pack and other systems. The processors communicate with other systems on the
vehicle via four interfaces: I Bus, K Bus, CAN and diagnostic DS2 Bus. An 8 Kbyte, non-volatile memory (EEPROM)
is provided for the storage of vehicle and instrument data (eg; mileage reading, service interval status).
The instrument pack also features a self diagnostic feature and on-board diagnostics via communication with
TestBook/T4.
Inputs are received as either analogue signals via conventional hardwired connections or as digital signals via multi-
channel connections with the bus systems. These signals are filtered and evaluated by the processors and the data
converted into actuation of the analogue gauges and indicator/warning lamps. The processors also function as a
gateway for the bus systems, processing data from one system and passing it to another.
The instrument pack receives and transmits data on five bus systems as follows:
Redundant Data Storage
In the event of a new instrument pack having to be installed, certain information needs to be maintained to prevent
data loss. This information is transferred continuously from the instrument pack on the I bus and is received and held
in an EEPROM in the LCM. The data is also stored, along with other vehicle specification data, in the immobilisation
ECU.
The data stored is as follows:
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Vehicle Identification Number (VIN)
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Total distance travelled
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Service interval fuel volume and type of last service
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Service interval clock.
When a new instrument pack is installed, the LCM will update the instrument pack EEPROM with the stored data
providing the following parameters are met:
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The VIN in the instrument pack and the LCM match
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The total distance reading in the instrument pack EEPROM is less than 158 miles (255 km)
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The total distance reading in the LCM EEPROM is less than 999,900 miles or kilometres or equal to or greater
than 0 miles or kilometres
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The total distance recorded in the instrument pack EEPROM is less than the distance travelled stored in the LCM
EEPROM.
Vehicle coding data, such as engine type, market, etc., is stored in the immobilisation ECU and retrieved by TestBook/
T4 and used to update the new instrument pack.
If the VIN in the instrument pack is set to 0, only service interval data is passed from the LCM EEPROM to the
instrument pack RAM, it is not stored in the instrument pack EEPROM. The total distance displayed in the odometer
LCD is frozen at the value stored in the instrument pack EEPROM.
If any of the stored data in the LCM EEPROM conflicts with the data within the instrument pack, a lamp, known as a
manipulation point, is illuminated in the pack. The manipulation point is located in the trip meter LCD, below the 'Miles'
text or next to the 'km' text.
Bus System
Single/Dual Line
Transmission/Baud Rate (Bd)
I Bus
1
9,600 Bd
K Bus
1
9,600 Bd
CAN
2
500.0 kBd
DS2 Bus
1
9,600 Bd
K line
1
10,400 Bd