Design

Design

Central electronic module (CEM)




The central electronic module (CEM) (4/56) is the master unit for the alarm.
The control module communicates with directly connected units, via the LIN and the controller area network (CAN). The control module has a number of sensors connected to it and determines what actions should be taken.

Switches in the lock units




A contact breaker is mounted in the lock units on the side doors and trunk lid/tailgate to indicate if any of them are open or closed. On vehicles with an alarm there is a single switch on the hood. The switches are closed when the door or tailgate/trunk lid is shut.
When the alarm is activated, the central electronic module (CEM) checks every 3 times / second that the switches are closed. If the central electronic module (CEM) detects that a switch is open the alarm is triggered.
If the central electronic module (CEM) detects that a switch is not closed when a lock command for locking the central locking system and alarm activation is received, the vehicle tilt sensor and movement sensor will not be activated. When the last door or hatch is closed, all alarm functions are activated, including movement sensor/vehicle tilt sensor after the initial time delay of 11 seconds.

Siren




The siren is used as a sound source for the alarm function. The siren is mounted under the cowl. From structure week 200946 the siren is fitted in the left-hand wheel housing, above/behind the wheel. The siren is available with or without an internal vehicle tilt sensor. The type of siren mounted in the vehicle is market and customer dependent.
The siren sounds if the power supply is cut or if ground is cut or if communication with the central electronic module (CEM) fails while the alarm is activated. The siren contains an internal battery which is charged when the ignition is on. The battery cannot be replaced by itself. The alarm cause can be read from the diagnostic tool. This states what caused the alarm.
If the vehicle is equipped with a siren with a vehicle tilt sensor, the sensor is integrated into the siren. The vehicle tilt sensor reacts to changes in the angle of lean or motion of the vehicle and transmits a signal to the central electronic module (CEM). While the vehicle tilt sensor is mounted in the siren it is counted as a separate unit. If the vehicle tilt sensor indicates that the vehicle is being lifted the central electronic module (CEM) must send an activation signal to the siren. In this case the siren cannot trigger an alarm by itself.
The siren is powered via a fuse from the central electronic module (CEM) The siren is grounded in the engine compartment.

Movement sensor (IMS)




The movement sensor (IMS) is in the interior light in the ceiling. On vehicles with panoramic roof the movement sensor is next to the rear dome lamp, for more info, see the chapter, Mass Movement Sensor Module (MMS), below. The movement sensor (IMS) is used to detect movement inside the passenger compartment when the alarm is activated.
When the alarm is activated, the central electronic module (CEM) checks the sensor.
The sensor communicates serially with the central electronic module (CEM).
When the sensor is activated it sends out ultrasound into the passenger compartment. The sound waves are reflected back to the sensor by the vehicle interior and if the sensor detects change in reflections or movements in the passenger compartment then the alarm is triggered. The sensor is also sensitive to air turbulence and therefore all windows and roof hatch, if appropriate, must be closed so that the sensor shall function optimally without the risk of false alarms.

Note! Due to the sensitivity of the sensor, the alarm can be triggered if an external passenger compartment heater is used for example.

Mass Movement Sensor Module (MMS) (only XC60 with panorama roof)




The Mass Movement Sensor Module (MMS) is located in the tunnel console under the cup holder.
The sensor is used to detect movements, primarily in the front of the passenger compartment, when the alarm is activated. On vehicles with panoramic roof there is also a movement sensor (IMS) located at the rear dome lamp.
When the alarm is activated, a check of the Mass Movement Sensor Module (MMS) is done by the Central electronic module (CEM).
The Mass Movement Sensor Module (MMS) communicates serially with the central electronic module (CEM).
The Mass Movement Sensor (MMS) uses microwaves to detect movement in the event of an activated alarm. No metal objects (coins, cans, etc.) or bottles of liquids should be placed over the sensor when the vehicle is alarmed as this greatly affects its function.

Alarm LED/Lock LED




The alarm LED is located on top of the dashboard. The LED is in the same housing as the sun sensor and twilight sensor. The LED is directly connected to the central electronic module (CEM). It is used to indicate alarm status.
When the alarm is activated, the LED will flash approximately once every two seconds.
If the alarm was triggered during the alarm cycle, the LED will flash rapidly, about 3 times per second, at unlocking. This continues until the remote control key is inserted into the starter unit or the starter button is pressed (only applies to vehicles with keyless locking system installed).
For S60 (11-)/V60, vehicles without alarm will still be equipped with alarm diode. For these vehicles the alarm diode will be used to indicate lock status.

Switch for reduced alarm (structure week -200746)




Switch for reduced alarm is located on the center console under the control unit for climate control. From and including structure week 200720 activation of reduced alarm takes place via the menu in the Infotainment control module (ICM). The switch is used to temporarily deactivate the vehicle tilt sensor and motion sensor functions. When the function is activated the doors are not deadlocked when the vehicle is locked. The function can only be connected up to one minute after the ignition has been switched off. If a longer time has passed the ignition must be turned to position I and back to 0 before the function can be activated.
The switch has an integrated LED to indicate when the function is activated. A message is displayed in the display in the driver information module (DIM).

Replacement of Siren control module (SCM) via the normal horn (structure week 200946-)
If the alarm system indicates break-in normally the Central electronic module (CEM) shall request activation of siren control module (SCM). If this cannot be done due to, e.g., disconnected siren control module (SCM), then the Central electronic module (CEM) activates the normal horn instead as replacement of siren control module (SCM).

Heartbeat sensor (structure week -201020)




The heart beat sensor is mounted against the body, to the right, under the floor in the cargo compartment. The sensor is only on vehicles with the keyless function. The sensor senses vibrations in the body that are created by somebody's heart beat inside the vehicle. The sensor can be activated from the remote key using the information button.

Note! The heartbeat sensor does not trigger the alarm functions in the vehicle. The sensor only indicates that somebody is in the vehicle in the event of a request from the remote key/Volvo Personal Communicator.

The heart beat sensor is directly connected to the central electronic module (CEM) and communicates serially via LIN with it.
The sensor is powered via a fuse from the central electronic module (CEM) and is grounded in the body.
The heartbeat sensor is only available on vehicles manufactured structure week -201020.

Remote key/Volvo Personal Communicator




The remote control key is used to activate and deactivate the alarm. The vehicle's alarm is fully activated (provided that the function for reduced alarm has not been activated) approximately 11 seconds after the vehicle has been locked using the remote control key's lock button (or with the lock button on the door handle for vehicles with keyless entry). The alarm is deactivated when the vehicle is unlocked using the remote control key button for unlocking the central locking system or for passive opening with Keyless vehicle module (KVM). There is a button on the remote control key for triggering the panic alarm function in order to attract attention in an emergency situation.

Note! (Applies only to vehicles with keyless function and heart beat sensor installed): There is a button on the remote control for reading off the vehicle's status and for activating the heart beat sensor. The status of the vehicle is indicated by LEDs on the remote key. For further information, see Function. On vehicles without heartbeat sensor (structure week 201020-) this button is used to show status for if the alarm has been activated.