Automotive Door Lock Operation

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1.Manual door locking / unlocking function
When the door lock control switch is operated on the lock/unlock side, the door lock/unlock signal is transmitted to the CPU in the integration relay.
After receiving the signal, CPU turns on Tr1 or Tr2 for about 0.2 seconds and also turns on the lock/unlock relay. In this state, the lock/unlock relay forms the ground circuit, the current flows from the battery to the ground through the motor, and all the door lock control motors rotate in the lock/unlock direction to turn off/on the door lock position switch.
Operation when the door is locked
Operation when the door is unlocked
In some vehicles, the door lock position switches are installed for all doors.
2.Door key-linked lock / unlock function
When the key is inserted in the door key cylinder and turned on the lock/unlock side, the key-operated switch is turned on the lock/unlock side to rotate all the door lock control motors in the lock/unlock direction as in the manual lock/unlock operation.
Operation when the door is locked
Operation when the door is unlocked
3.Two-step unlock function (driver’s door)
When the key is turned to the unlock direction once, only the door is mechanically unlocked. In this state, the UL3 terminal of the integration relay is grounded via the key-operated switch once, but Tr2 is not turned on. If the key is turned in the unlock direction twice within three seconds, the UL3 terminal is grounded twice and the CPU in the integration relay turns Tr2 on.
Consequently, the unlock relay is turned on and all the doors are unlocked.
When the door key unlock operation is performed only once
When the door key unlock operation is performed sequentially twice
4.Key confine prevention function
When the driver’s door is open and the key is left in the ignition key cylinder, the CPU in the integration relay turns Tr2 on for about 0.2 seconds after the door lock knob is operated to the lock position (with the door lock position switch off).
Consequently, the unlock relay is turned on and all the doors are unlocked. If the door lock control switch is operated to lock the doors in this state, all the doors are locked once and then unlocked same as above.
When the door lock knob is on the unlock side
When the door lock knob is operated to the lock side
5.Security function
When the doors are locked by any of the operations in (1), the security function in the integration relay disables the unlock operation by the door lock control switch (for manual operation). Any of the operations in (2) will cancel the security function.

(1)Operations that set door lock security function
Locking all doors with the key on the driver’s or front passenger’s doors
Locking the doors with the transmitter (including 30-second auto lock)
Locking the driver’s door by the keyless locking method (lock with the inside door lock knob and close the door)
(2)Operations that cancel the security function
Unlocking all doors with the key on the driver’s or front passenger’s doors
Unlocking the doors with the transmitter
Unlocking the driver’s door with the knob
After the door lock security function is set, the key confine prevention function unlocks the doors.

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