Locking - Keyless Vehicle Module (KVM)

Courtesy of VOLVO CARS CORPORATION

Locking takes place when one of the lock sensors on the door handles is affected. A ground signal is forwarded from the lock button to the keyless vehicle module (KVM), which in turn, activates the inner antennas. An encrypted command is transmitted out to the passenger compartment that any remaining remote keys must not respond to the command. This is because the magnetic field from the external antennas can also reach inside the vehicle.

Then the keyless vehicle module (KVM) activates the antenna in the rear door handle on the side of the vehicle where the lock button was pressed in and transmits a request for a remote key. The encrypted response from the remote key contains, among other things, the remote key's ID code and is received by the remote keyless entry (RKE). The keyless vehicle module (KVM) checks the identity of the remote key against the programmed codes. If the remote key is approved, the keyless vehicle module (KVM) transmits a signal to the central electronic module (CEM) to lock the vehicle.

After the vehicle has been locked, the inner antennas in the passenger compartment and luggage compartment reactivate to find out if there are any remote keys left in the vehicle. If there are, the Keyless vehicle module (KVM) registers the identity of the remaining remote keys and will not use signals from them. This applies until the vehicle is unlocked the next time.

This is done so that the remaining remote keys cannot be used to unlock the vehicle "passively" or start the vehicle from the outside. The function of the deactivated remote keys is reset when the vehicle is unlocked by another authorised remote key or if the unlocking button is pressed on one of the deactivated remote keys. Resetting also occurs when the remote key is inserted in the ignition.

If the vehicle is locked by one of the lock buttons on the remote key being pressed, there is no communication between the keyless vehicle module (KVM) and the remote key. The keyless vehicle module (KVM) then only receives a message from the remote key checks if it is approved and then sends a lock command to the central electronic module (CEM). In this instances locking is fully controlled by the central electronic module (CEM). However, if any remote keys are left inside the vehicle, they will be deactivated in the same way as above.