Mass Movement Sensor Module (MMS)

Fig 1: Locating Mass Movement Sensor Module (MMS)

Courtesy of VOLVO CARS CORPORATION

NOTE:

For XC90 MY 2012- the Mass movement sensor module (MMS) is replaced with ultrasonic sensor module (IMS).

The mass movement sensor module (MMS) detects movements inside the passenger compartment using high frequency radio waves. The Doppler effect principle is used to determine whether the frequency of the received microwave is different from the transmitted microwave. If the frequency has changed, this is interpreted as a movement in the vehicle. If a movement is detected, a trigger signal is transmitted to the upper electronic module (UEM) which activates the alarm.

Mass movement sensors (MMS) are located in the ceiling, in the center of the vehicle, to optimally cover as much as possible of the vehicle's volume. In XC90 there are two mass movement sensors (MMS), one front and one rear. These are connected in parallel to the central electronic module (CEM) and share wiring for voltage supply and communication.

The mass movement sensor module (MMS) is powered from the upper electronic module (UEM) and earthed in the body.

There are diagnostics for the mass movement sensor module (MMS).