Power Locks: Description and Operation

Power Door Locks/Keyless Entry/Security System

How the Circuit Works

The power door locks, keyless entry, and security alarm are part of the multiplex integrated control system. The use of multiplexing incorporates all three systems together.

The following multiplex control units operate the systems:
- Driver's MPCS unit
- Front passenger's MPCS unit
- MICU
- Relay control module

Power Supply
Battery voltage is supplied at all times through fuse 7 (in the driver's under-dash fuse/relay box) to the driver's MPCS unit and to the driver's door outer handle light/touch sensor. Battery voltage is also supplied at all times through fuse 7 (in the driver's under-dash fuse/relay box) to the front passenger's MPCS unit and to the front passenger's outer handle light/touch sensor.

Battery voltage is supplied at all times through fuse 8 (in the driver's under-dash fuse/relay box) to the MICU The MICU is also located in the driver's under-dash fuse/relay box.

Battery voltage is supplied in ON or START through fuse 21 (in the driver's under-dash fuse/relay box) to the driver's MPCS unit.

System Description

Door Locks (Switch Operation)
The driver's door lock switch links directly to the driver's MPCS unit and the front passenger's door lock switch links directly to the front passenger's MPCS unit. All lock and unlock commands from this switch are communicated across the multiplex integrated control system to the MICU.

According to the switch request, the MICU directly operates the power supply and the grounding signals to the reversible door lock motors for lock and unlock modes. Locking the doors from the driver's door lock switch will lock all the doors.

Inserting the built-in key into the driver's door key cylinder switch and turning the built-in key one time will unlock the driver's door. Turning the built-in key a second time will unlock all the doors. This is a multiplex controlled response.

The following control signals are multiplex communicated to the MICU.
- Driver's door key cylinder switch
- Driver's door lock actuator switch
- Driver's door lock switch
- Driver's outer door handle light/touch signal
- Front passenger's door lock actuator switch
- Front passenger's door lock switch
- Front passenger's outer door handle light/touch signal
- Keyless access control unit

Door Locks (Remote Transmitter Operation)
The doors can be locked or unlocked by using the keyless access remote transmitter.

The keyless remote request is communicated across the multiplex integrated control system to the MICU. According to the command, the MICU directly operates the power supply and the grounding signals to the reversible door lock motors for lock and unlock modes. Pressing the unlock button one time will unlock the driver's door. Pressing the unlock button a second time will unlock all the doors. This is a multiplex controlled response. Pressing the lock button of the keyless transmitter will lock all the doors, and set the security system.

Security
The security alarm is incorporated with the power door locks and keyless entry. When the vehicle is locked by the driver's door key cylinder switch, door lock switch, or the remote transmitter, the security alarm is activated.

The security alarm monitors the following signals:
- Audio unit connection
- Door lock actuator switches
- Door switches
- Ignition key switch
- Security hood switch
- Trunk latch switch

When any of the monitored systems are disturbed, the alarm is triggered. Along with the inability to start the vehicle, the taillight relay and the horn relay are energized. The exterior lights will flash and the horns will sound for 2 minutes.