Siren Control Module (SCM)

Fig 1: Locating Siren Control Module

Courtesy of VOLVO CARS OF NORTH AMERICA.

Information transmitted by the siren control module (SCM) to the upper electronic module (UEM) contains configuration and status information. This data is carried via serial communication.

When the alarm is activated the siren sends continuous status signals to the upper electronic module (UEM).

The siren has a battery and a built in battery charger so that it is independent of the power supply in the car. The battery charger maintains battery voltage in the integrated battery. When the alarm is activated, the power supply for the siren and the serial communication between the siren and the upper electronic module (UEM) are monitored. The siren sounds if the car's power supply to the siren is broken or if communication between the upper electronic module (UEM) and the siren is interrupted. The battery and battery charger in the siren cannot be replaced separately. The entire siren must be replaced in the event of a fault.

The siren is in a protected location under the fender liner in the front right-hand wheel arch. The siren must be configured after replacement. Configuration is carried out using the appropriate diagnostics tool.

There are diagnostics for the siren.