Mass Movement Sensor Module (MMS)

Fig 1: Identifying Mass Movement Sensor Module (MMS)

Courtesy of VOLVO CARS CORPORATION

The mass movement sensor module (MMS) detects movements inside the passenger compartment using high frequency radio waves of 2.45 GHz. 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 central electronic module (CEM) which activates the alarm.

The mass movement sensor (MMS) is in the headlining in the center of the vehicle. This ensures optimum coverage of the interior of the vehicle. There are two sensors in five door cars. One is positioned in the center of the roof and the other in the roof above the cargo compartment.

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