Operating principles (Freelander 2)

Front seats with electric adjustment without memory

The driver's seat without the position memory function works in all ignition power modes. The driver's seat without the position memory function works only when the ignition is set to power mode 6 (ignition).

Power for the front passenger seat is supplied from the AJB through the passenger seat power relay to the passenger seat control switch module. Power for the driver seat is supplied directly from the AJB to the driver seat control switch module. Power to the front passenger seat and to the driver seat is controlled by the CJB. When the seat control switch is pressed, the seat switch module sends voltage to the appropriate seat adjustment motor. Each seat adjustment switch has two pin contacts. Both contacts are normally connected to ground.

The driver and passenger seat switch units are also connected in circuit to the battery drain timer relay located in the CJB and controlled by the CJB. The battery drain timer relay allows the driver and front passenger seat position to be adjusted for 10 minutes after the engine is switched off and in the appropriate ignition supply mode. The 10-minute timer is reset if the appropriate ignition supply mode is maintained and the driver's door is opened or closed. Operation of the driver and front passenger seat is immediately inhibited when the vehicle is centrally locked.



Pressing the seat adjustment motor control switch applies voltage to one of the contacts, while the other contact remains grounded. Pressing the seat adjustment motor control switch in the opposite direction reverses the voltage and ground, causing the motor to rotate in the opposite direction. If the mechanism jams, an internal thermal relay stops supplying voltage to the motor.

Driver's seat with electric adjustment and memory function

The driver's seat with position memory function works when the ignition is set to power mode 4 (accessory power) and power mode 6 (ignition), and does not work in mode 9 (engine start).

Power for the driver's memory seat is supplied directly from the AJB to the seat control module. The memory seat switch pack is connected to the seat control module, which controls the operation and stored position of the individual seat adjustment motors. The power seat control module is connected via the medium speed CAN bus to the CJB and the left and right door control modules.

The seat control module is also connected in circuit to the battery drain timer relay located in the CJB and controlled by the CJB. The battery drain timer relay allows the seat position to be adjusted for 10 minutes after the engine is switched off and in the correct ignition supply mode. The 10-minute timer is reset if the correct ignition supply mode is maintained and the driver's door is opened or closed. Operation of the driver's seat is immediately inhibited when the vehicle is centrally locked.



Requests to move the outside mirrors to recall the stored position are transmitted via the medium speed CAN bus by the seat control module to the front door control modules. The front door control modules directly control the storing and recall of the stored positions of the outside mirrors. For more information, refer to the chapter: Rearview Mirrors (501-09 Rearview Mirrors, Description and Function).

Seat control module

The seat control module has driver-selectable functions and automatic control functions.

Driver selectable functions

• Recalling the seat and exterior mirror position settings from memory
• Direct seat adjustment

Function for recalling the settings of the seat position and exterior mirrors from memory

The recall function sets the driver's seat to a position stored in memory and is activated by pressing the memory button of the switch block. To limit the power consumption when recalling adjustments, only 2 seat adjustment motors are activated at a time. To further minimize the current load when supplying power to the motors, the initiation of each of the two operating motors is carried out in a phased manner with a delay of 10 milliseconds. First, the longitudinal displacement of the seat and the change in the angle of the backrest occur, and then the height of the seat cushion is adjusted.

When the seat switch cluster memory button is pressed, the seat control module transmits a message via the medium speed CAN bus to the front door control modules. The door control modules then activate the recall of the stored exterior mirror positions. The instrument cluster information center will display the recall messages when this function is activated.



The recall function works with two separate modes; the operation of each mode depends on the vehicle status when the seat position memory button is pressed.

Modes of operation of the settings call function:
One-click mode
When the vehicle is stationary and the switch cluster memory button is pressed, the setting recall function will operate in one-touch mode. One-touch mode allows the seat and outside mirrors to immediately move to the requested position stored in memory.

If the seat position is adjusted or the memory button is pressed while recalling the settings in one-touch mode, the current recall of the settings will be cancelled and the seat (and the outside mirrors via the medium-speed CAN bus) will immediately stop moving. The seat will then move in the direction corresponding to the switch pressed.

Recalling the memory settings is also immediately cancelled if the vehicle starts moving before the seat reaches the requested position.

Proportional mode
When the vehicle is moving and the switch cluster memory button is pressed, the memory recall function will operate in proportional mode. Proportional mode recalls the seat position (and outside mirrors) as long as the memory switch is held down. When the memory button is released, memory recall immediately stops until the seat has reached the target position stored in memory.

In order to reach the intended position stored in memory while the vehicle is moving, it is necessary not to release the memory button until all movements of the seat and outside mirrors are completed.

Direct seat adjustment function

The direct seat adjustment function is activated by pressing the seat position adjustment switch on the switch block (tilt, horizontal or height adjustment).

When any of the seat adjustment switches is pressed, the motor will adjust in the corresponding direction until the switch is released. Only two seat adjustment motors can operate at a time.

Automatic control functions

The seat control module has the following automatic control functions:

• Mechanism jam detection mode
• Standby mode
• Battery Monitoring Mode

Mechanism jam detection mode

The system detects that the seat movement motor is stuck if, with the motor running, the input feedback signal from the corresponding sensor does not change for 200 milliseconds while movement is occurring along that axis.

If the seat control module detects that the mechanism is jammed, movement along the corresponding axis is cancelled, both for the case of a position recall from memory (recalling a setting from memory) and when pressing a switch (direct seat adjustment).

During any manual movement during direct seat adjustment, the seat control module remembers and stores the point at which the jam occurs. If the movement continues beyond the jam point stored in the memory, the stored position is deleted from the seat control module memory. This occurs whenever the mechanism moves beyond the stored jam point (e.g. when the switch is pressed for more than 2 seconds).

If the motor stops due to a jam (e.g. due to difficulty in moving the seat), after the obstacle has been removed, the movement along the given axis can be restarted to pass the new jam point. To do this, press and hold the corresponding switch for more than 2 seconds. If you do not press the switch in such a way as to pass the new jam point, this position will be stored in the memory of the seat control module as a complete movement along the corresponding axis.



If the motor stops due to a break in communication with the sensor (sensor or wiring failure), the movement along this axis can be restarted to pass the jam point. To do this, press the corresponding switch. To do this, press and hold the corresponding switch for more than 2 seconds. In this way, you can maintain control of the motor when the feedback signal from the sensor is lost.

If the sensor returns a pulse signal after movement is resumed, the movement will continue until the switch is released or until the mechanism stops again due to jamming. If the feedback is not resumed, the motor will only run for 0.5 seconds and then stop until the switch is released and pressed again for more than 2 seconds, after which the motor will be activated again for 0.5 seconds, etc. This is the so-called "slow motion mode".

If the medium speed CAN data bus fails, the seat will operate in "slow motion mode".

NOTE: For diagnostic purposes, when the seat is in "slow travel mode", a mid-speed CAN bus disconnect indication appears and the seat control module or CJB or door control modules do not appear connected to the mid-speed CAN bus.

Standby mode

The seat control module has a sleep mode to reduce power consumption to the necessary minimum.

If the seat control module cannot enter the standby mode due to motor operation, a reset request, or a switch press, it will enter the standby mode immediately after the operation is completed.

NOTE: When recalling adjustments from memory, all adjustments will be completed before the seat control module enters standby mode, not just the one being performed by the currently running motor.

The seat control module will exit standby mode when CAN bus activity is detected.

Battery Monitoring Mode

The seat control module monitors the incoming electrical power to ensure that the battery voltage is sufficient to crank the engine. If the battery voltage drops below 10.5 volts, the seat control module ignores all requests to recall the mirror and seat settings from memory until the voltage exceeds 11.0 volts.

When the battery voltage drops below 8.5 V, the seat control module ignores all requests to move the seat until the voltage exceeds 9.0 V.

If the battery voltage is greater than 16.5 V, the seat control module ignores all requests to move the seat until the voltage drops below 16.0 V.