Description

Instrument Cluster

NOTE:
A = Hardwired; D = High Speed CAN bus; N = Medium Speed CAN bus; O = LIN bus









OPERATION
The instrument cluster receives a permanent battery voltage supply via a fuse in the RJB (rear junction box). High speed and medium speed CAN (controller area network) buses are also connected to the instrument cluster to receive information from other system control modules for instrument cluster functions.
The speedometer is driven by high speed CAN (controller area network) signals transmitted by the ABS (anti-lock brake system) module. The wheel speeds are measured by sensors reading the rotational speed of the wheels from toothed targets on the hubs. The wheel speeds are passed from the sensors to the ABS (anti-lock brake system) module in the form of pulsed signals. The ABS (anti-lock brake system) module converts these signals into a speed output on the high speed CAN (controller area network) to the instrument cluster.
The tachometer is driven by an engine speed signal transmitted on the high speed CAN (controller area network) from the ECM (engine control module). The signal is derived from the CKP (crankshaft position) sensor. The signal is received by the instrument cluster microprocessor and the output from the microprocessor drives the tachometer.
The steering column lock is connected directly to the instrument cluster. The steering wheel switches are also connected directly to the instrument cluster via the steering wheel module. Other vehicle sensors are connected to the CJB (central junction box) which processes the signals from the sensors and passes them to the instrument cluster on the high speed or medium speed CAN (controller area network) bus. The ambient temperature signal is received by the ECM (engine control module) which processes the signal and passes the information to the instrument cluster on the high speed CAN (controller area network) bus.

DESCRIPTION

INSTRUMENT CLUSTER













ANALOGUE INSTRUMENTS
The analogue instruments located in the instrument cluster are as follows:
- Speedometer
- Tachometer.
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 gages return to their respective zero positions when the ignition is switched off.

Speedometer
The speedometer is driven by square wave signals derived from the wheel speed sensors and the ABS (anti-lock brake system) module. The signal is received via the ECM (engine control module) on the high speed CAN (controller area network) bus.

Tachometer
The tachometer is driven by an engine speed signal transmitted on the high speed CAN (controller area network) from the ECM (engine control module). The signal is derived from the CKP (crankshaft position) sensor.

MESSAGE CENTER
For additional information, refer to Information and Message Center Locations

WARNING INDICATORS
The warning indicators are located in various positions in the instrument cluster. The warning indicators can be split into two groups; self controlled and externally controlled.
Self controlled warning indicators are dependent on software logic within the instrument pack for activation. The pack software controls the 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 controlling module or illuminated by the instrument cluster on receipt of a bus message from another subsystem module.
Some indicators are activated by an external subsystem module but the instrument cluster contains the control logic.

DIAGNOSTICS

Car Configuration File (CCF)
The Car Configuration File (CCF) contains all relevant data about the specification and market condition of the applicable vehicle, immobilization codes and driver personal settings. This information is retained in the CJB (central junction box) and is read by the instrument cluster, enabling the cluster to detect which systems and components are fitted to the vehicle. This information is continuously sent to the instrument cluster on the medium speed CAN (controller area network) bus. The instrument cluster also backs up the CCF in it's internal memory.
The CCF will also need to be updated using an approved Land Rover diagnostic system if the vehicle is modified in service from its original factory specification. This can include fitting non-standard wheels and/or tires, optional accessory dealer fit components with an electrical interface, i.e. park distance control.