JAGUAR XFR 2010 1.G Workshop Manual

rear window heater switch is pressed or the engine stops.

Automatic operation during a journey is initiated when low ambient air temperatures are experienced and the vehicle has been
travelling for a set period of time above a threshold speed. In this instance, no feedback is given to the driver to inform him
the rear window heater is operational (the switch LED is not illuminated). The duration of heater operation is variable depending on the ambient air temperature, vehicle speed and the amount of time the vehicle has been travelling.

Windshield Heater (Where Fitted)

Windshield heater operation is only enabled when the engine is running. The ATC module controls operation of the windshield heater using two relays in the EJB (engine junction box). When windshield heater operation is required, the ATC module broadcasts a message to the CJB on the medium speed CAN bus. On receipt of the message, the CJB energizes the relays by providing a ground path for both relay coils. This allows a battery feed to flow across the relays to power the windshield left
and right heater elements.
There are two modes of windshield heater operation; manual and automatic.

Manual operation is activated by pressing the windshield heater switch on the integrated control panel. When the switch is
pressed, the status LED in the switch illuminates and the windshield heater elements are energized. Manual operation is discontinued when the windshield heater switch is pressed a second time, 5 minutes have elapsed (the heating phase), or the
engine stops. If manual operation is discontinued by the engine stopping, the previous heating phase is resumed if the engine
is re-started within 30 seconds.

There are two variants of automatic operation; automatic operation at the start of a journey and automatic operation during a
journey.

Automatic operation at the start of a journey is initiated if the ambient air temperature is below 5 °C (41 °F). In this instance,
the switch LED is illuminated and the heater elements are energized for 6.5 minutes. Automatic operation is discontinued if the windshield heater switch is pressed or the engine stops.

Automatic operation during a journey is initiated when low ambient air temperatures are experienced and the vehicle has been
travelling for a set period of time above a threshold speed. In this instance, no feedback is given to the driver to inform him
the windshield heater is operational (the switch LED is not illuminated) and the duration of operation is variable depending upon the ambient air temperature, vehicle speed and the amount of time the vehicle has been travelling.

Exterior Mirror Heaters

Operation of the exterior mirror heaters is fully automatic and not controllable by the driver. Exterior mirror heater operation is
determined by ambient air temperature and windshield wiper status. When ambient air temperature reaches a pre-determined
level, the ATC module broadcasts an exterior mirror heating request to the door modules over the medium speed CAN bus. On receipt of this message, the door modules provide feed and ground connections to both exterior mirror heater elements.

The amount of time the exterior mirror heaters are operational increases if the windshield wipers are switched on. This ensures
the mirrors remain mist free in damp and wet conditions, where there is an increased risk of misting.

Seat Heaters (Where Fitted)

There are four seat heater settings available; off, 1, 2 and 3, which can be selected on the home and climate control screens
of the TSD. The heat setting is relayed to the vehicle occupants through a graduated display on the TSD.

Operation of the heated seats is controlled by the ATC module. When the ATC module receives a heating request from the TSD, it broadcasts a message to the CJB over the medium speed CAN bus. The CJB then provides a hardwired 12 V supply to the three heater elements in the related front seat. The heater elements, two in the seat cushion and one in the seat squab,
are wired in series. The ATC module monitors seat temperature using a temperature sensor located in each seat cushion. The CJB provides the temperature sensors with a 5 V supply. The level of the returned voltage back to the CJB is proportional to the seat temperature. The value of the return signal is broadcast to the ATC module, over the medium speed CAN bus, which allows it to control the seat temperature to the required level. The ATC module will suspend or disable operation of the seat heaters if any of the following occur:

Battery voltage exceeds 16.5 ± 0.3 V for more than 5 seconds. Seat heating is re-enabled when battery voltage
decreases to 16.2 ± 0.3 V.
If a short or open circuit is detected.
If the seat heat temperature rises significantly above the target temperature setting.

The graduated display on the TSD remains illuminated until the seat heaters are turned off or the engine stops. If the engine
is restarted within 30 seconds the seat heater resumes the previous heating level.

bus. Temperature control for the heater element is provided by the steering wheel heater control module which receives a
temperature feedback signal from a NTC (negative temperature coefficient) thermistor located within the steering wheel.



ATC Module Component Description



The ATC module is mounted on the outboard end of the air inlet duct, behind the front passenger side of the instrument panel. The ATC module processes inputs from the TSD, the switches on the integrated control panel and the system sensors. In response to these inputs, the ATC module outputs control signals to the A/C system and the heating and ventilation system.
Two electrical connectors provide the interface between the ATC module and the vehicle wiring. The ATC module uses hardwired inputs from the system sensors, the LIN bus to communicate with the stepper motors and the medium speed CAN bus to communicate with other control modules on the vehicle.

A/C Compressor Solenoid Valve

The A/C compressor solenoid valve is integral with the A/C compressor. Operation of the solenoid valve is controlled by the ATC module using a hardwired drive current of differing values. By controlling the flow of refrigerant through the compressor, the
solenoid valve can control the A/C system pressure and the evaporator operating temperature.
Refrigerant Pressure Sensor



The refrigerant pressure sensor provides the ATC module with a pressure input from the high pressure side of the refrigerant system. The refrigerant pressure sensor is located in the refrigerant line between the condenser and the thermostatic
expansion valve.

The ATC module supplies a 5 V reference voltage to the refrigerant pressure sensor and receives a return signal voltage, between 0 V and 5 V, related to system pressure.

The ATC module uses the signal from the pressure sensor to protect the refrigerant system from extremes of pressure. The ATC module transmits the A/C pressure, along with the compressor drive current value, to the instrument cluster on the medium speed CAN bus. These signals are broadcast to the ECM on the high speed CAN bus to allow it to calculate the torque being applied to the engine by the compressor. www.JagDocs.com

pressure:

Decreases to 2.1 ± 0.2 bar (31.5 ± 3 lbf/in²); the ATC module loads the A/C compressor again when the pressure increases to 2.3 ± 0.2 bar (33.4 ± 3 lbf/in²).
Increases to 31 ± 1 bar (450 ± 14.5 lbf/in²); the ATC module loads the A/C compressor again when the pressure decreases to 26 ± 1 bar (377 ± 14.5 lbf/in²).

Evaporator Temperature Sensor



The evaporator temperature sensor is a NTC thermistor that provides the ATC module with a temperature signal from the downstream side of the evaporator. The evaporator temperature sensor is mounted directly onto the evaporator matrix fins.

The ATC module uses the input from the evaporator temperature sensor to control the load of the A/C compressor and thus the operating temperature of the evaporator.

A capacitive sensor element to measure humidity.
A motor driven fan to draw air through the sensor and over the sensing elements.

The humidity sensor element is built out of a film capacitor on different substrates. The dielectric is a polymer which absorbs
or releases water proportional to the relative humidity of the air being drawn through the sensor, and thus changes the
capacitance of the capacitor. For protection, the sensor element is contained in a nylon mesh cover.

Humidity within the passenger compartment is controlled by raising and lowering the evaporator temperature. An increase in
evaporator temperature increases the moisture content of the air entering the passenger compartment. Lowering the
evaporator temperature reduces the moisture content of the air entering the passenger compartment. Humidity and Temperature Sensor

1 LH door mirror 2 Ambient air temperature sensor The ambient air temperature sensor is a NTC thermistor that provides the ATC module with an input of external air temperature. The sensor is hard wired to the ECM and its signal is transmitted to the instrument cluster on the high speed CAN bus. The instrument cluster acts as a gateway and transmits the ambient air temperature signal to the ATC module on the medium speed CAN bus. The sensor is installed in the LH door mirror, and is accessed by removing the mirror glass, cap and actuator.

Sunload Sensor



The sunload sensor consists of two photoelectric cells that provide the ATC module with inputs of light intensity; one as sensed coming from the left of the vehicle and one as sensed coming from the right. The inputs are a measure of the solar
heating effect on vehicle occupants, and are used by the ATC module to adjust blower speed, temperature and distribution to improve comfort.

The sensor is installed in the speaker grill on the upper surface of the instrument panel. Power for the sensor is provided by a
5 V feed from the instrument cluster.
The sensor also contains the active anti-theft alarm indicator.
Refer to: Anti-Theft - Active (419-01 Anti-Theft - Active, Description and Operation). Ambient Air Temperature Sensor

as nitrous oxides, sulphur oxides and carbon monoxide. The sensor is attached to the center of the upper front crossmember.

The pollution sensor is powered by an ignition controlled voltage feed from the CJB and provides the ATC module with separate signals of hydrocarbon and oxidized gas levels. With a pollution sensor fitted, the ATC module can control the air inlet source to reduce the amount of contaminants entering the passenger compartment. This function is fully automatic, but can be
overridden by manual selection of the air source using the recirculation switch on the integrated control panel.
If there is a fault with the sensor, the ATC module disables automatic operation of the recirculation door.

Climate Control - Ambient Air Temperature Sensor
Removal and Installation

Removal


NOTE: Removal steps in this procedure may contain installation details. Published: 11-May-2011

1. Refer to: Exterior Mirror Cover (501-09 Rear View Mirrors, Removal and Installation).

2.
3. www.JagDocs.com

Climate Control - Blower Motor
Removal and Installation

Removal


NOTE: Removal steps in this procedure may contain installation details. Published: 11-May-2011

1. Refer to: Battery Disconnect and Connect (414-01 Battery, Mounting and Cables, General Procedures).

2.