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

A = HARDWIRED;

AN = HIGH SPEED (HS) CONTROLLER AREA NETWORK (CAN) POWERTRAIN BUS;

AP = MEDIUM SPEED (MS) CAN COMFORT BUS.

1. Instrument Cluster (IC)
2. Head Up Display Cooling Fan Control Module (HUDCFCM)
3. Head Up Display (HUD) Control Module
4. Central Junction Box (CJB)
5. Engine Control Module (ECM)
6. Anti-lock Braking System (ABS) Control Module
7. Electric Steering Column Lock (ESCL) Control Module
8. Ground
9. Power Supply
10. Central Junction Box (CJB)

HEAD UP DISPLAY (HUD) - CONTROL DIAGRAM

A = HARDWIRED;

AP = MEDIUM SPEED (MS) CONTROLLER AREA NETWORK (CAN) COMFORT BUS.

1. Head Up Display (HUD) Control Module
2. Head Up Display Cooling Fan Control Module (HUDCFCM)
3. Instrument Cluster (IC)
4. Ground (2 off)
5. Power Supply

Instrument Cluster / Description and OperationInstrument Cluster / Diagnosis and Testing

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