Land Rover Discovery: Instrument Cluster / Operation
INSTRUMENT CLUSTER (IC)
The Instrument Cluster (IC) receives a permanent battery voltage supply via
Rear Junction Box (RJB). A High Speed (HS) Controller Area Network (CAN)
powertrain bus and Medium Speed (MS) CAN comfort bus are also connected to the
IC which communicates with other control modules.
The speedometer is driven by HS CAN signals transmitted to the Anti-Lock
Brake System (ABS) control module. The wheel speed sensors are measured
by sensors reading the rotational speed of the wheels from toothed targets
on the hub. The wheel speeds are passed from sensors to the ABS control
module in the form of pulsed signals. The ABS control module converts
theses signals into a HS CAN to the IC.
The tachometer is driven by an engine speed signal transmitted on the HS
CAN from the Engine Control Module (ECM). The signal is derived from the
Crankshaft Position (CKP) sensor. The signal received by the IC
microprocessor and the output from the microprocessor drives the
tachometer.
The Electric Steering Column Lock (ESCL) is connected directly to the
Instrument Cluster (IC). The steering wheel switchpack inputs are sent to the
IC via the Local Interconnect Network (LIN) input. Other vehicle sensors are
connected to the Central Junction Box (CJB) which processes the signals
from the sensors and passes them to the IC on the High Speed (HS)
Controller Area Network (CAN) powertrain bus. The Ambient Air
Temperature (AAT) signal is received by the Engine Control Module (ECM)
which processes the signal and passes the information to the Automatic
Temperature Control Module (ATCM) unit which sends the signal to the IC.
HEAD UP DISPLAY (HUD)
The Head Up Display (HUD) is controlled from the Instrument Cluster (IC)
message center menu.
When selected, the menu offers the following options:
- Selecting the position of the display on the windscreen.
- Display brightness.
- Selecting which information is displayed on the HUD.
Control of the display brightness can be adjusted in three different ways:
- As listed above, manually, from within the Instrument Cluster (IC) Head
Up
Display (HUD) control message center menu.
- If the vehicle lighting is switched on, the HUD display will adjust
simultaneously with the manual adjustment of the IC panel light dimmer
switch.
- Automatic brightness, controlled using data from the forward ambient
light sensor, housed in the rain sensor.
- Prior to selecting the HUD windscreen position the user should select
their
desired seating position. The steering wheel controls are used to set the
horizontal position of the windscreen display. Once set, the information can
be saved in the seat memory control system, storing the selected
preferences.
CONTROL DIAGRAM
INSTRUMENT CLUSTER (IC) - CONTROL DIAGRAM
![INSTRUMENT CLUSTER (IC) - CONTROL DIAGRAM](images/books/227/index415(1).jpg)
A = HARDWIRED;
AN = HIGH SPEED (HS) CONTROLLER AREA
NETWORK (CAN) POWERTRAIN BUS;
AP = MEDIUM SPEED (MS) CAN
COMFORT BUS.
- Instrument Cluster (IC)
- Head Up Display Cooling Fan Control Module (HUDCFCM)
- Head Up Display (HUD) Control Module
- Central Junction Box (CJB)
- Engine Control Module (ECM)
- Anti-lock Braking System (ABS) Control Module
- Electric Steering Column Lock (ESCL) Control Module
- Ground
- Power Supply
- Central Junction Box (CJB)
HEAD UP DISPLAY (HUD) - CONTROL DIAGRAM
![HEAD UP DISPLAY (HUD) - CONTROL DIAGRAM](images/books/227/index416(1).jpg)
A = HARDWIRED;
AP = MEDIUM SPEED (MS) CONTROLLER AREA
NETWORK (CAN) COMFORT BUS.
- Head Up Display (HUD) Control Module
- Head Up Display Cooling Fan Control Module (HUDCFCM)
- Instrument Cluster (IC)
- Ground (2 off)
- Power Supply
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PRINCIPLES OF OPERATION
For a detailed description of the Instrument Cluster, refer to the relevant
Description and Operation section in the workshop manual. REFER to:
Instrument Cluster (413-01 Instr
REMOVAL
NOTES:
LH illustration shown, RH is similar.
Removal steps in this procedure may contain installation details.
The ignition must be switched off.
WARNING:
Make sure to support the vehicle
SEE MORE:
SPECIAL TOOL(S)
REMOVAL
WARNING:
Be prepared to collect escaping fluid.
NOTE:
Some variation in the illustrations may occur, but the essential
information is always correct.
WARNING:
Make sure to support the vehicle with axle stands.
Raise and support the vehicle.
Refer to: Transmission - INGENIUM
If DTC B1252-19 (USB Port General Electrical Failures -
Circuit current above
threshold) has been logged, the IAM has detected a current draw from the
Portable Audio Interface Panel in excess of 1.7 Amps. In these
circumstances, the power supply to the Portable Audio Interface Panel will
be cut for