Security Alarm System

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

The security alarm system is integrated with the multiplex integrated control system. For the system to arm, the ignition switch must be in the LOCK (0) position, the key must be removed, and the MICU must receive signals that the doors, hood, and tailgate are closed and locked. The alarm can be armed or disarmed at any time by locking or unlocking the driver's door with the key or pressing the LOCK/UNLOCK button on the transmitter. The alarm can also be armed by locking (with the lock knob) then closing the driver's door.

When everything is closed and locked, the only inputs that are grounded, and have 0 V, are the driver's door lock knob switch (LOCK position), and the audio unit. In other words, all of the other switches are open, and have about 5.0 V in sleep mode or 12 V in awake mode, including the key cylinder switches. The security indicator in the gauge control module begins to flash immediately after the doors, tailgate, and hood are closed and locked, and then, after 20 seconds, the flashing intervals of the security indicator change to indicate that the alarm is fully armed. If the security indicator does not flash, the system is not arming. If the LOCK button is pressed a second time within 5 seconds (Keyless LOCK acknowledgment is turned ON) and the vehicle is completely closed and locked, the keyless buzzer sounds, and the parking lights and the side marker lights flash one time to confirm the security alarm system is armed.

If one of the switches is misadjusted or shorted internally (0 V), or there is a short in the circuit (0 V), the security system will not arm. 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 vehicle, or something 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, the 5-12 V reference drops to 0 V, and the system sounds the alarm. If the audio unit is disconnected, the input loses its ground, and the input voltage goes to 5-12 V, and the system sounds the alarm.

The system sounds the alarm when any of following occur while the security system is armed:

A door or the tailgate is forced open
A door is unlocked without using the key or the transmitter
The hood is opened
The audio unit (or navigation unit, rear controller and screen) is disconnected
The transmitter panic is operated
The ignition switch is turned ON (II)

When the system sounds the alarm, the horns sound, and the parking lights and the side marker 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 transmitter.