Siren control module (SCM)
The siren is used as the acoustic source for the alarm function. The siren is located in a protected position under the fender liner in the right front wheel housing.
The siren begins to sound if the power supply is cut or if communication with the upper electronic module (UEM) stops when the alarm is activated. The siren has an internal battery that is charged when the ignition is switched on. This battery can complete approximately 10 alarm cycles and has a limited service life depending on the climate in which it is used. The battery cannot be replaced as a separate component. The cause of the alarm can be read off and verified via VIDA.
The siren is powered via a fuse from the central electronic module (CEM) The siren is grounded in the engine compartment.
There are diagnostics for the siren (SCM).