Keyless Entry/Security Alarm System Description

Security Alarm System


The security alarm system is armed automatically after the doors, hood, and trunk are closed and locked. For the system to arm, the ignition switch must be off, the key must be removed, and the MICU must receive signals that the doors, hood, trunk are closed and locked. The alarm can be disarmed at any time by unlocking the driver's door with the key or pressing the UNLOCK button on the remote transmitter.

When everything is closed and locked, the only inputs that are grounded, and have 0 volts, are the driver's door lock knob switch (LOCK position), and the audio-HVAC-display unit. In other words, all of the other switches are open, including the key cylinder switches, and they have about 10 volts. The security indicator in the gauge control module begins to flash immediately after the vehicle is complately closed and locked. 15 seconds after the doors are locked with the key the security system arms and the security indicator flashes on for a shorter amount of time than before. If the security indicator does not flash, the system is not arming. A beep to confirm the security alarm system is armed will sound if the LOCK button is pressed a second time within 5 seconds.

If one of the switches is misadjusted or there is a short in the curcuit, the security system will not arm. As long as the control unit continues to receive a ground signal, it senses that the vehicle is not closed and locked, and the system will not arm. Conversely, a switch that is slightly misadjusted can cause the alarm to sound for no apparent reason. In this case, a significant change in outside air temperature, the vibration of a passing truck, or someone bumping into the vehicle could cause the alarm to sound. There is no glass breakage or motion detector feature.

If anything is opened or improperly unlocked after the system is armed, the control unit receives a ground signal from that switch, and the 10 volts reference drops to 0 volts. If the audio-HVAC-display unit is disconnected, the input loses its ground, and the input voltage goes to 10 volts. The system sounds the alarm when any of these things occur:

When the system sounds the alarm, the horns sound and the exterior lights flash for 2 minutes. The alarm can be stopped at any time by unlocking the driver's door with the key or by pressing any button on the remote transmitter.

Keyless Entry System


The keyless entry system is integrated with the MICS.
The multiplex integrated control unit (MICU) receives LOCK, UNLOCK and PANIC signals from the door multiplex control unit (keyless receiver).
The keyless entry system allows you to lock and unlock the vehicle with the remote transmitter.
When you press the LOCK button, all doors lock. When you press the UNLOCK button once, only the driver's door unlocks. The other doors will unlock when you press the button a second time.

When the switch for the ceiling light is in the center position, it will come on when the UNLOCK button is pressed. If a door is not opened, the light will go off in about 30 seconds, and the doors will relock. If the doors are locked with the remote transmitter within 30 seconds, the light will go off immediately.

The doors will not lock with the remote transmitter if a door is not fully closed, or if the key is in the ignition switch.

If the keyless unlock button is pressed, released, then pressed and held, the windows will begin to open. The windows stop if the button is released. See power windows for more information and troubleshooting.

Ultrasonic System (KE model)


KE model has the ultrasonic system. The system is constituted by the ultrasonic sensor and the alarm control siren that is a combined ACU and self powered siren.

The ultrasonic sensor uses the ultrasonic Doppler technology. It saturates the volume of the car with 40 kHz ultrasounds, convert the received signal that is generated by any moving target inside the volume into a rectangular wave characterized by the Doppler frequency, which is analysed by a dedicated algorithm, in-built the microcontroller.

The alarm control siren communicates with the ultrasonic sensor and the security control unit. If the alarm control siren receives an arm command from the security control unit, it enters the arm mode after default period time (stored in EEPROM memory) of 10 seconds.

If the alarm control siren receives alarm command from the ultrasonic sensor and the security control unit during arm condition, alarm control siren activates the internal siren.

The system has the power supply line ‘+ B Tamper' function (cutting wire protection). If one or both power supply wires (+ B, GND) are tampered during arm condition, the system changes to alarm mode. If the alarm condition remains, the alarm control siren will trigger in alarm 10 times (programmable in EEPROM memory).

The system has the serial line ‘alarm comm line tamper' function (not authorized disarm attempt. If wrong identification code is received by the ACU, the system changes to alarm mode. The alarm control siren will generate up to 10 alarm triggers for each arm cycle (programmable in EEPROM memory).

The system has the serial line ‘alarm comm line polling' function (connection monitoring). If this wire is interrupted during arm mode the system change to alarm condition. If the alarm condition remains, the alarm control siren will trigger in alarm 10 times (programmable in EEPROM memory).