Instrument Cluster / Carrier: Description and Operation

Instrument Cluster

COMPONENT LOCATION









INTRODUCTION
The instrument cluster is located in the instrument panel, above the steering column. The instrument cluster comprises analogue gauges, an Liquid Crystal Display (LCD) message center to provide vehicle operation details to the driver and a number of indicator lamps to display system status.
The message center is a LCD located in a central position in the cluster. The message center displays system status information including fuel quantity remaining.
The instrument cluster also functions as an intelligent controller for a number of other vehicle systems, for example column adjust positions, steering column multifunction switch inputs, steering Servotronic control.
The instrument cluster is the gateway for the high speed and medium speed Controller Area Network (CAN) and is also connected to the Local Interconnect Network (LIN) bus to the start control unit and the steering wheel module.

ANALOGUE GAGES

Speedometer
The speedometer is located on the Left Hand (LH) side of the cluster and is available in three market variants:
- major scale Miles Per Hour (MPH), minor scale kilometers per hour (km/h)
- major scale km/h, minor scale MPH
- major scale km/h only.
The speedometer is driven by high speed CAN signals transmitted by the Anti-lock Brake System (ABS) module. The wheel speeds are measured by sensors reading the rotational speed of the rear wheels from toothed targets on the hubs. An average of the two wheel speeds are passed from the sensors to the ABS module in the form of pulsed signals. The ABS module converts these signals into a speed output on the high speed CAN to the instrument cluster.
The same speed outputs from the wheel speed sensors are also used to calculate the distance the vehicle has travelled.

Tachometer
The tachometer is located on the Right Hand (RH) side of the instrument cluster and displays engine speeds up to 8000 Revolutions Per Minute (RPM) on naturally aspirated models and 7000 RPM on supercharged models.
The tachometer is driven by an engine speed signal transmitted on the high speed CAN from the Engine Control Module (ECM). The signal is derived from the Crankshaft Position (CKP) sensor. The signal is received by the instrument cluster microprocessor and the output from the microprocessor drives the tachometer.

LCD DISPLAY
In the area above and below the message center is a LCD display. The area below the message center displays a linear fuel gage, odometer, trip distance and trip computer readouts. The area above the message center displays the transmission gear position information and speed control related information.

NOTE:
There is no engine coolant temperature gage displayed. If the engine coolant temperature increases to above a predetermined threshold, a warning message is displayed in the message center. The message is sent from the ECM in a high speed CAN message to the instrument cluster.


Fuel Gage
The linear fuel gage has a colored bar which moves left or right depending on the tank contents. As the bar moves to the left the fuel tank contents displayed is decreasing. A warning message is displayed in the message center when the fuel tank contents fall to below the reserve level.
The fuel gage is controlled by CAN messages from the Auxiliary Junction Box (AJB). The AJB reads the values output by the fuel level sensors every 131 ms and transmits a fuel tank contents value, corrected for battery voltage, in a CAN message to the instrument cluster.
A fuel pump symbol is displayed to the left of the linear gage. An arrow above the symbol shows the driver on which side of the vehicle the fuel filler cap is located.
Above the linear fuel gage, is a LCD area which displays odometer and trip readouts. When a trip computer function is selected, these are replaced by a trip computer display for the trip function selected.

Transmission Gear Position Display
The gear position display shows selector lever position or selected gear when using the 'Jaguar Sequential Shift'.
The gear selector module transmits a CAN message to the instrument cluster for gear selector lever position. The module also outputs a 'not in park' signal to the instrument cluster.
The Transmission Control Module (TCM) transmits a high speed CAN message to the instrument cluster with data containing the selected gear when in Jaguar Sequential Shift mode.

Message Center
The message center displays system status and warning messages to the driver. For additional information, refer to Information and Message Center Description and Operation

WARNING INDICATORS









The warning indicators are located in various positions in the instrument cluster. The indicators can be split into two groups; instrument cluster controlled and externally controlled.
Instrument cluster controlled warning indicators are dependant on software logic within the instrument cluster for activation. The cluster software controls the indicator illumination check at ignition on.
Externally controlled indicators are supplied with current from another vehicle system control module or illuminated by the instrument cluster software on receipt of a bus message from another vehicle sub-system. The indicator illumination check at ignition on is also controlled by the sub-system module on these indicators.

CONTROL DIAGRAM

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









PRINCIPLES OF OPERATION

Warning Indicator Functionality









The functionality for each of the above warning indicators is described in the following section.

1 and 2. Turn Signal Indicators
The turn signal indicators are controlled by the Central Junction Box (CJB) on receipt of medium speed CAN signals from the instrument cluster.
The instrument cluster outputs a voltage to the turn signal indicator switch. The switch contains resistors of different values. When the switch is operated in either the LH or RH direction, the voltage is passed to a ground connection in the instrument cluster which detects the reduced voltage supplied via the resistors. When the turn signal indicator switch is operated in the LH or RH direction, the instrument cluster detects the ground voltage and determines whether a LH or RH selection is made.
The instrument cluster transmits a medium speed CAN message to the CJB for operation of the applicable turn signal indicators. The message can contain a number of states for each possible switch position and also an out of range low and high state for circuit faults and an initial value for the switch neutral position. The turn signal indicators are not subject to the 3 second indicator check when the ignition is switched on.
The AJB software controls the flash rate of the warning indicator which sends 'ON' and 'OFF' signals to the instrument cluster which flashes the indicators in a green color. During normal operation, the warning indicator flashes slowly, accompanied simultaneously by a sound from the instrument cluster sounder. If a fault exists, the CJB transmits a message to the instrument cluster which responds by flashing the warning indicator and operating the sounder at double speed to indicate a bulb failure and also displays an appropriate message and vehicle graphic in the message center.
The hazard warning indicators are controlled by the CJB on receipt of a completed ground path from the hazard warning indicator switch. The CJB outputs a medium speed CAN message to the instrument cluster which operates both the LH and RH turn signal indicators simultaneously. The hazard warning indicators can operate with the ignition switched off, therefore the CAN message from the CJB will also carry a 'wake-up' message for the instrument cluster.

3. Brake Warning Indicator
This warning indicator is displayed in a red or amber color (dependant on market) as a brake symbol in all markets except USA which have the word 'BRAKE' in addition to the symbol. The indicator is controlled by high speed CAN messages from the ABS module and the parking brake control module. The indicator is illuminated in a red color for a 3 second indicator check when the ignition is switched on.
The ABS module monitors the fluid level in the brake fluid reservoir using a level switch. If the fluid level falls to below a determined level, the switch contact is broken and the ABS module detects the low fluid level condition. The ABS module issues a CAN message which is received by the instrument cluster which illuminates the warning indicator and displays the message 'BRAKE FLUID LOW' in the message center. The warning indicator can also be illuminated by the ABS module if an Electronic Brake Distribution (EBD) fault is detected.

NOTE:
If both the brake warning indicator and the ABS warning indicator illuminate simultaneously, a major fault in the brake system will have occurred.
The warning indicator also displays parking brake status. When the parking brake is applied, the warning indicator will be illuminated by the instrument cluster and, if the vehicle is moving, the message 'PARK BRAKE APPLIED' will be also displayed in the message center in response to a CAN message from the parking brake control module.
If a condition exists where the parking brake cannot be applied, the parking brake control module issues a CAN message to the instrument cluster which illuminates or flashes (dependant on market) the warning lamp on and off and is accompanied with a message 'CANNOT APPLY PARK BRAKE'. If a fault occurs in the parking brake system, the parking brake control module issues a CAN message to the instrument cluster which illuminates the warning indicator and displays the message 'PARK BRAKE FAULT' in the message center.

4. Forward Alert Indicator
The forward alert system uses the components of the adaptive speed control system to alert the driver of the presence of a vehicle ahead. The system can be turned on and off using a switch located in the auxiliary lighting switch when the adaptive speed control system is off. The indicator is illuminated in an amber color for a 3 second indicator check when the ignition is switched on.
The forward alert system is controlled by the adaptive speed control module. When the switch is pressed, the forward alert system is activated and the adaptive speed control module issues a forward alert active message on the high speed CAN bus to the instrument cluster. The forward alert icon in the instrument cluster will illuminate in an amber color and a 'FORWARD ALERT' message will be displayed in the message center. When the button is pressed a second time, the module issues a forward alert off CAN message. The forward alert system will be deactivated, the forward alert icon will go off and a message 'FORWARD ALERT OFF' will be displayed in the message center.

5. Automatic Speed Limiter (ASL) Indicator
The ASL is controlled by the ECM. An ASL switch is located in the floor console, adjacent to the gear selector lever. When the ASL switch is pressed, this is sensed by the ECM which issues a high speed CAN message to the instrument cluster. The instrument cluster illuminates the ASL warning indicator in an amber color to show the driver that ASL is active. The driver sets the required speed using the speed control SET +/- switches on the steering wheel. The selected speed is shown by the message ' LIMITER SET XXX MPH / K/MH' in the message center. The indicator is illuminated in an amber color for a 3 second indicator check when the ignition is switched on.
ASL can be deselected by pressing the ASL switch, by depressing the throttle pedal initiating kick-down or by pressing the 'cancel' switch on the steering wheel. The ASL indicator will go off and the message center will display the message 'limiter cancelled' for 4 seconds.
If a fault occurs in the ASL system, the ECM will send a message to the instrument cluster to illuminate the ASL indicator and display the message 'LIMITER NOT AVAILABLE'.

6. Adaptive Speed Control Indicator
The adaptive speed control system is controlled by the adaptive speed control module. Operation of the SET +/- switches on the steering wheel will activate the system. Operation of the switches is detected by the adaptive speed control module. The module issues a high speed CAN message to the instrument cluster which illuminates the adaptive speed control indicator, when the system is in 'follow mode', in an amber color and displays a 'SETSPEED XXX MPH / KM/H' message in the message center. The indicator is illuminated in an amber color for a 3 second indicator check when the ignition is switched on.

7. Anti-lock Braking system (ABS) Warning Indicator
The ABS warning indicator is controlled by the ABS module. If a fault in the ABS system is detected by the ABS module, the module issues a high speed CAN message to the instrument cluster to illuminate the ABS warning indicator in an amber color and display the message 'ABS FAULT' in the instrument cluster. The indicator is illuminated in an amber color for a 3 second indicator check when the ignition is switched on. If a fault is present when the ignition is on the bulb will remain illuminated after the 3 second indicator check period.

NOTE:
The 'ABS FAULT' message is not displayed in NAS markets.

NOTE:
If both the ABS warning indicator and the brake warning indicator illuminate simultaneously, a major fault in the brake system will have occurred.
On all vehicles except NAS, the ABS warning indicator is also used for parking brake faults. The indicator in these markets illuminates in an amber color and displays a brake symbol without the text 'ABS' in the icon.
On NAS vehicles, the ABS warning indicator is only used for ABS. The warning indicator has 'ABS' on the icon and will illuminate in a amber color for ABS faults only.

8. Adaptive Front light System (AFS) Warning Indicator
The AFS warning indicator is controlled by the AFS control module. The AFS warning indicator illuminates in an amber color if a fault in the AFS system is detected by the control module. If a fault in another system occurs which prevents AFS operation, the warning indicator will flash. The indicator is illuminated by the instrument cluster on receipt of a high speed CAN message from the AFS control module. The indicator is illuminated in an amber color for a 3 second indicator check when the ignition is switched on.

9. Engine Malfunction Indicator Lamp (MIL)
The MIL warning indicator is controlled by the ECM and illuminated by the instrument cluster on receipt of a message on the high speed CAN bus from the Engine Control Module (ECM). The indicator is illuminated in an amber color for a 3 second indicator check when the ignition is switched on.
If the MIL remains illuminated after the engine is started or illuminates when driving, a fault is present and must be investigated at the earliest opportunity. Illumination of the MIL warning indicator alerts the driver to an On-Board Diagnostic (OBD) fault which will cause excessive emissions output. This may relate to either an engine management system fault or a transmission fault.

10. Tire Pressure Monitoring System (TPMS) Warning Indicator
The TPMS warning indicator is illuminated by the instrument cluster on receipt of a medium speed CAN message from the TPMS module. The indicator is illuminated in an amber color for a 3 second indicator check when the ignition is switched on.
If the indicator illuminates and is accompanied by the message 'TIRE PRESSURE SYSTEM FAULT' in the message center, then a TPMS fault has occurred. If the indicator illuminates and accompanied by a different message, then a low tire pressure has been detected, a spare wheel has been fitted or a TPMS sensor has failed.

11. Airbag Warning Indicator
The airbag warning indicator is controlled by the instrument cluster. The indicator is illuminated in an amber color for the 3 second indicator check when the ignition is switched on. The indicator remains illuminated after the 3 second period has expired until the instrument cluster receives a turn off message on the high speed CAN bus from the Restraints Control Module (RCM).

12. Front Fog Lamp Indicator
The green colored front fog lamp indicator is controlled by the CJB and illuminated by the instrument cluster on receipt of a front fog lamp on message on the medium speed CAN bus from the CJB. The indicator is illuminated for as long as the front fog lamps are active. The front fog lamp indicator is not subject to the 3 second indicator check when the ignition is switched on.

13. Dynamic Stability Control (DSC) Indicator
The DSC warning lamp is controlled by the ABS module and illuminated by the instrument cluster in response to messages received on the high speed CAN bus. The indicator is illuminated in an amber color for the 3 second indicator check when the ignition is switched on.
The DSC warning indicator, are permanently illuminated in an amber color if the instrument cluster receives a high speed CAN message from the ABS module relating to one of the following faults:
- Traction control fault
- Yaw control fault
- Engine drag torque control fault
- Panic Brake Assist (PBA) fault
- Signal missing relating to either traction control active, yaw control active or DSC switch input.
The above faults will also generate an applicable DSC and ABS warning message in the message center.
The DSC warning indicator will flash at 2 Hz for if the traction control or yaw control is active when the DSC system is enabled.
If the DSC system is switched off, the warning indicator will be permanently illuminated until the DSC system is subsequently re-activated.

14. Safety Belt Warning Indicator
The safety belt warning indicator operates for both the driver and passenger safety belts. The warning indicator is controlled by the RCM and illuminated by the instrument cluster on receipt of high speed CAN bus messages. The safety belt warning indicator is not subject to the 3 second indicator check when the ignition is switched on.
The operation of the passenger seat buckle switch is as described below with the exception that the instrument cluster must receive a hardwired signal from the belt minder control module to indicate that a passenger is occupying the seat.
The safety belt warning indicator is subject to a timer. The warning indicator is activated when the following conditions exist:
- Ignition is switched on
- One of the front seat belts is unbuckled
- USA market only - 75 seconds has elapsed after ignition on mode is selected
- Vehicle is not in reverse gear
- Vehicle speed is more than 8 km/h (5 mph).
Once the above parameters are met, the instrument cluster flashes the warning indicator at 2 Hz for 10 seconds accompanied by a simultaneous chime. After 10 seconds the chime ceases and the warning indicator is permanently illuminated for 20 seconds. This sequence is repeated every 30 seconds until one of the following events occurs:
- 300 seconds has elapsed
- The safety belt of the occupied front seats is fastened
- The ignition is switched to off mode
- The vehicle speed decreases to below 5 km/h (3 mph).

NOTE:
On USA market vehicles, the warning indicator is not permanently illuminated.
In certain markets the belt minder function can be enabled and disabled using the driver safety belt switch. For additional information, refer to Safety Belt System Description and Operation

15. Side Lamp Indicator
The instrument cluster controls the green colored side lamp indicator on receipt of a side lamp status message on the medium speed CAN bus from the CJB and the AJB. The lighting switch on the Left Hand (LH) steering column multifunction switch is connected to the instrument cluster. Selections using this switch are detected by the cluster which requests the side or headlamp operation via a CAN message to the CJB and the AJB. The CJB and the AJB responds with a side lamp active message and the cluster illuminates the side lamp indicator. The side lamp indicator is not subject to the 3 second indicator check when the ignition is switched on.

16. High Beam Indicator
The instrument cluster controls the blue colored high beam indicator on receipt of a high beam status message on the medium speed CAN bus from the CJB. The lighting switch on the Left Hand (LH) steering column multifunction switch is connected to the instrument cluster. High beam or flash selections using this switch are detected by the cluster which requests the light operation via a CAN message to the CJB. The CJB responds with a high beam active message and the cluster illuminates the high beam indicator. The high beam indicator is not subject to the 3 second indicator check when the ignition is switched on.

17. Rear Fog Lamp Indicator
The amber colored rear fog lamp indicator is controlled by the AJB and illuminated by the instrument cluster on receipt of a rear fog lamp on message on the medium speed CAN bus from the AJB. The indicator is illuminated for as long as the rear fog lamps are active. The rear fog lamp indicator is not subject to the 3 second indicator check when the ignition is switched on.