Seating: Other Jaguar XJ X351

CONTROL DIAGRAM

Note. A = Hardwired; N = medium speed controller area network (CAN) bus; O = local interconnect network (LIN) bus.

Adjustment - Non-Memory Front Seat

Scheme 173

Adjustment - Memory Front Seat

Scheme 174

Heated Seats

Climate Seats

Scheme 175

Seat Massage

Scheme 176

FRONT SEATS

Adjustment - Non-memory Seats

On non-memory front seats, each seat switch pack receives three permanent power supplies; two from the central junction box (CJB) and one from the rear junction box (RJB). The power supplies from the central junction box (CJB) are used to operate the adjustment motors. The power supply from the rear junction box (RJB) is used to operate the air pump and associated solenoid valves.

For the adjustment motors, when a switch is operated power is connected to the applicable side of the related motor and a ground is connected to the opposite side of the motor, which then runs in the required direction. To move the motor in the opposite direction the polarity is reversed.

When the lumbar inflate switch is pressed, power is connected to the air pump to inflate the support. When the deflate switch is pressed, power is connected to the deflate solenoid valve, which opens to deflate the support.

Adjustment - Memory Seats

On memory front seats, the seat module receives three permanent power supplies; two from the central junction box (CJB) and one from the rear junction box (RJB). The power supplies from the central junction box (CJB) are used to operate the adjustment motors. The power supply from the rear junction box (RJB) is used to operate the seat module.

Permanent power supplies are also connected from the central junction box (CJB) to the memory switch pack and from the rear junction box (RJB) to the seat switch pack.

The seat switch pack is connected to the seat module by a local interconnect network (LIN) bus for the seat adjustment switches. Any selection for seat adjustment generates a message which is passed via the local interconnect network (LIN) bus to the seat module. The seat module processes the request and operates the applicable seat motor as required using the power supplies from the central junction box (CJB).

The seat module on the driver seat is also connected to the medium speed controller area network (CAN) bus. This allows the driver seat module to monitor the position of the door mirrors and the steering column, using signals from the door modules and central junction box (CJB) respectively, when storing and recalling memory settings.

The memory switch pack has two hardwired connections with the related seat switch pack. One is for the three channel switches and one is for the memory switch. Operation of the any of the memory switches is relayed from the seat switch pack to the seat module on the local interconnect network (LIN) bus.

Memory settings are stored in the seat module by pressing the memory switch and then, within 5 seconds, one of the channel switches. When the memory switch is pressed the light emitting diode (LED) in the switch comes on. After the channel switch is pressed, the light emitting diode (LED) goes off and a chime sounds to confirm that the settings have been memorized. If the ignition is on, the message center will display a confirmation message. Any previously stored settings on the selected channel will be over-written.

Memory settings are recalled by pressing the applicable channel switch. If the ignition is on, the message center will display a confirmation message.

On seats with 2-way lumbar adjustment, when the inflate switch is pressed power is connected to the air pump to inflate the support. When the deflate switch is pressed, power is connected to the deflate solenoid valve, which opens to deflate the support.

On seats with 4-way lumbar adjustment and bolster adjustment, when an inflate switch is pressed, power is simultaneously connected to the air pump and the related inflate solenoid valve. When a deflate switch is pressed, power is connected to the related deflate solenoid valve, which opens to deflate the support. On vehicles with massage seats, power is connected to the inflate and deflate solenoid valves in the same way, but when an inflate selection is made the air pump is activated by a local interconnect network (LIN) bus message to the master solenoid valve, which then operates the air pump.

Stall Detection

A seat adjustment motor is deemed to have stalled if there is no change in the input from the feedback sensor of the motor for 200 ms. If a stall condition is detected then the drive to that motor is cancelled for the remainder of the memory recall operation or until the switch is re-selected (manual movement). The motor may be activated again, to move past the stall position, by pressing the appropriate switch for more than 2 seconds. If sensor feedback is detected, then the motor will continue to be driven until the switch is released. If sensor feedback is not detected, then the motor is only driven for 0.5 second and then stops until the switch is released and pressed again, when a further 0.5 second of activation is permitted. This is known as inch mode, which allows seat adjustment to be maintained if sensor feedback is lost.

Initialization

When a replacement seat module is fitted, it should be calibrated using Jaguar approved diagnostic equipment so that the module can learn the positions of the adjustment motors.

Battery Monitor

If the battery voltage drops below 10.5 V, then the driver seat module ignores all requests for a memory recall until the battery voltage has reached 11.5 V. This will conserve as much power in the vehicle battery as possible to enable engine cranking.

Massage Seats

Seat massage requests from the START / STOP buttons on the TSD are sent via the medium speed controller area network (CAN) bus to the appropriate seat module. The seat module processes the requests and transmits them to the master massage solenoid on the local interconnect network (LIN) bus connection.

When a START button is pressed, the master massage solenoid operates the relevant master and slave solenoid valves and activates the pump. The massage function operates in 10 minute cycles. After a 10 minute cycle is complete the user must re-select the function if a further 10 minute cycle is required.

When a STOP button is pressed, the 10 minute cycle is completed, or the ignition is switched off, the solenoid valves are opened to deflate the massage cells and the air pump turned off.

During operation the bottom cell pair inflate and then deflate. As the first cell pair are deflating the second cell pair start to inflate. This sequence is repeated for all five cell pairs, from cell pair one at the bottom to cell pair five at the top. Cell inflation time, which varies between cell pairs, is as follows

1. Cell pair one - 3 seconds.
2. Cell pair two - 2.6 seconds.
3. Cell pair three - 2.8 seconds.
4. Cell pair four - 2.2 seconds.
5. Cell pair five - 1.6 seconds.

Anti-whiplash System

Depending on the weight of the occupant and the severity of the collision, the mechanisms begin to operate at a relative impact speed of between approximately 8.7 and 11.2 mph (13.9 and 17.9 km/h). At the point of a rear impact, the forward energy of the impact and the inertia of the occupant combine to push the backrest against the occupant's back. That causes the AWS mechanism to begin a controlled sequence of movements. First, while remaining in an upright position, the backrest moves rearwards by approximately 50 mm. Next, the backrest reclines through an angle dependent upon the direction and relative speed of the collision, up to a maximum of approximately 15 degrees.

The combined effect of these movements is to absorb some of the energy of the impact and reduce the relative acceleration of head and body, thereby helping to reduce the possibility of whiplash injury.

HEATED SEATS

The heater elements only operate when the engine is running. Power for the heater elements is supplied to the seat heater modules from the heated seat relay in the rear junction box (RJB), which is controlled by a hardwired ignition signal from the central junction box (CJB).

Seat heating selections made on the TSD and the rear climate control panel are transmitted to the automatic temperature control (ATC) module. Refer to Heating and Ventilation information.

When the automatic temperature control (ATC) module receives a seat heating request, it sends a local interconnect network (LIN) bus message to the appropriate seat heater module to energize the heater elements in the cushion and the squab. The seat heater module relays the temperature signal, from the thermal sensor in the cushion heater element, back to the automatic temperature control (ATC) module. The automatic temperature control (ATC) module uses the temperature signal to regulate the heater elements at the selected heat setting.

CLIMATE SEATS

The heating/cooling of the climate seats only operates when the engine is running. Power for the climate modules is supplied to the climate seat control modules by two permanent power supplies from the central junction box (CJB). The climate seat control modules also receive a power supply from the ignition relay in the central junction box (CJB).

Heating/Cooling selections on the TSD and the rear climate control panel are transmitted to the appropriate climate seat control module on the medium speed controller area network (CAN) bus. The climate seat control module then energizes the Peltier cell and the blower of the climate module(s) in the appropriate seat. The climate seat control module uses the signals from the temperature sensors in the squab and the cushion climate modules to regulate the seat at the selected temperature. If full seat heating/cooling is selected, both the squab and the cushion climate modules are activated. If partial seat heating/cooling is selected, only the squab climate module is activated.

MASSAGE SEATS

Where fitted, the massage system in each seat consists of an air pump, air cell pads, master and slave solenoid valve blocks. The air pump is also used for adjustment of the lumbar and squab bolster supports. The slave solenoid block also incorporates the solenoid valves used to control the squab bolster supports.

Operation of the massage system is controlled with START and STOP buttons on the climate menu of the TSD and is independent of the lumbar and squab bolster adjustments.

Air Pump

The air pump is located underneath the seat at the rear of the squab. The pump is housed inside a noise, vibration and harshness (NVH) casing to cut down the pump operation sound level. Operation of the air pump is controlled by the master solenoid valve block.

The maximum pump pressure is controlled by a pressure relief valve in the lumbar solenoid valve block. The maximum pressure range is 310.5 to 379.5 mbar (4.5 to 5.5 lbf/in 2 .).

A thermal protection device in the air pump stops pump operation if the temperature increases to 72±4 °C (162±7 °F). The pump will not re-start until 10 minutes after the temperature decreases below the cut-off temperature.

Solenoid Valves

Scheme 177

The master and slave solenoid valve blocks control the air supply to the massage air cells. During air cell deflation excess air is exhausted to atmosphere through the relevant solenoid valve block exhaust port.

Air Cell Pads

Scheme 178

The massage air cells are located in two pads in the front of the seat squab. The lower pad contains three separate pairs of cells, the upper pad contains two separate pairs of cells.

During operation the pressure of the air cells is approximately 207 to 379 mbar (3 to 5.5 lbf/in 2 .). This variation is due to the inflate time given to each air cell, the flow rate of the pump and the maximum pressure of the system.

Heated seats incorporate heater elements in the cushion and the squab of the seat. Power to the heater elements of the front seats is controlled by two seat heater modules attached to a bracket on the cabin floor, under the carpet at the front left corner of the left-hand (LH) front seat. Power to the heater elements of the two outside rear seats is controlled by two seat heater modules attached to a bracket on the back of the rear seat squab.

Each cushion heater element has a thermal sensor, which supplies a feedback temperature signal to the related seat heater module. The squab heater elements do not have a thermal sensor, and are regulated at the same temperature as the cushion heater elements.

Seat heating for the front and rear seats can be selected on the climate menu of the TSD. Seat heating for the rear seats can also be selected on the rear climate control panel. Three levels of heating are available. Heating can also be selected for either the cushion and the squab or just the squab.

Climate seats incorporate climate modules in the cushion and the squab of the seat. Operation of the climate modules of the front seats is controlled by a climate seat control module attached to a bracket on the cabin floor, under the carpet at the front left corner of the left-hand (LH) front seat. Operation of the climate modules of the two outside rear seats is controlled by a climate seat control module attached to the body, behind the of the rear seat squab.

The climate modules contain Peltier cells, which heat up or cool down depending on the voltage provided by the climate seat control module. Each climate module also contains a blower, which blows air over the Peltier cell to distribute the heated or cooled air through liners in the related cushion or squab. The blower is also controlled by the climate seat control module.

Seat heating and cooling for the front and rear seats can be selected on the climate menu of the TSD. Seat heating and cooling for the rear seats can also be selected on the rear climate control panel. Three levels of heating and three levels of cooling are available. Heating and cooling can also be selected for either the cushion and the squab, or just the squab.

Touch Screen Display

Scheme 179

Rear Climate Control Panel

Scheme 180

SEATS VEHICLES WITH: CLIMATE CONTROLLED SEATS

For a detailed description of the seating systems and operation, refer to Component Location and Overview and System Operation And Component Description .

CONNECTOR AND PIN INFORMATION

1. If any unit reads greater than 10 ohms, replace only that defective unit
2. If all units read less than 10 ohms but faults are still suspected, do not replace any units. Refer to step 4 below
3. As a final check, when a faulty unit has been identified strip the seat to access unit connector, Refer to: «Seats - Removal And Installation»(ref-570078-S20376987112013083000000) and re-check ohm reading to confirm greater than 10 ohms prior to removing unit
4. In cases where the above diagnostic routine does NOT identify a failed unit, please refer to "Over Temperature and Fluid/Air Leak Diagnostics" below. Also check for any live technical service bulletins referring to the seat climate system