DOOR / HATCH: POWER BACK DOOR SYSTEM: SYSTEM DESCRIPTION (2008 LX570)

SYSTEM DESCRIPTION

1. GENERAL

(a) The power back door unit (power back door ECU) receives a switch signal from the back door control switch, power back door control switch, or transmitter switch, operates the power back door motor built into the unit, and causes the back door to automatically open and close.

(1) The power back door system begins open operation after receiving a switch signal under the following conditions:

The power back door main switch is on (not pushed).
The tail gate is closed.
The shift lever is in P.
The power back door sensor circuit is not open.
The vehicle speed is 3 km/h (2 mph) or less.

(2) The power back door system begins close operation after receiving a switch signal under the following conditions:

The power back door main switch is on (not pushed).
The shift lever is in P.
The vehicle speed is 3 km/h (2 mph) or less.

(3) As the power back door ECU stores information about the position of the back door, when the battery, any of the fuses, or the power back door unit is removed/installed, perform initialization. If initialization is not performed, the power back door system will not function normally.

(4) When the power back door system begins operation, the buzzer sounds and the hazard warning lights flash to indicate the beginning of the operation.

(5) When the motor senses resistance during the close operation, it will change to the opening operation (jam protection function).

(6) Operating any power back door switch when the back door is fully closed inputs a request signal to the power back door ECU. The power back door ECU then outputs a "latch release" command to the back door lock in response to the input.

(7) The latch can be released only when the back door is unlocked.

(8) 3 switches are built into the back door lock, and the power back door ECU monitors the status of each switch. The power back door ECU controls latch "release/close" operations in response to the inputs from each switch.

Switch	Function
Back door courtesy switch	Detects whether back door is open or closed. This switch turns on when back door is open or ajar and turns off when it is fully closed.
Half-latch switch	Detects ajar position of latch. This switch turns on when latch is in open-latch position.
Closer position switch	Detects fully closed position of latch. This switch turns on when latch is in over-latch position.

(b) Function of main components.

Component	Function
Power back door main switch	According to whether the power back door main switch is turned on/off, the system operation will be as follows: When the power back door main switch is on (not pushed), the power back door system operation is disabled. When the power back door main switch is off (pushed), the power back door system operation is enabled.
Combination switch (Power back door control switch)	This switch sends a power back door open/close signal to the power back door ECU to open/close the back door.
Back door control switch	This switch sends a power back door close signal to the power back door ECU to close the back door.
Transmitter switch	By pressing the power back door switch on the transmitter, the power back door open/close operation is performed (pressing the switch during the open/close operation causes the opposite operation to begin).
Power back door warning buzzer	This buzzer sounds for 0.8 seconds when the power back door system begins operate.
Hazard warning light	The power back door ECU sends a power back door system operation start signal to the main body ECU which causes the hazard warning lights to flash twice.