Function

Function

Locking




Locking takes place when one of the lock buttons on the door handles is pressed in. A ground signal is forwarded from the lock button to the keyless vehicle module (KVM), which in turn, activates the inner antennas. A 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 response from the remote key contains, among other things, the remote key's ID code and is received by the remote keyless entry (TRX). 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. The vehicle cannot be locked from the boot lid.
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 authorized 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 into the Start control module (SCU).
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.

Unlocking




Two micro-switches are closed if a door handle is pulled out. A switch in the handle closes first followed by a switch in the quick lock.
When the contact breaker in the handle is closed, the keyless vehicle module (KVM) activates the antennas in the handle on the rear doors on the side on which the handle was pulled out. A request is transmitted via the antenna to the passive remote key. The remote key transmits an encrypted response which is received by the remote keyless entry (TRX) receiver. The remote keyless entry (TRX) receiver checks that the received signal is from a Volvo remote key. If it is, the message is forwarded to the keyless vehicle module (KVM). The keyless vehicle module (KVM) decrypts the signal and compares the received code from the remote key with its own programmed codes. If these correspond, the keyless vehicle module (KVM) transmits two signals. One signal is transmitted to the quick lock, in the door on which the handle was pulled out, to unlock and open the door. The other signal is transmitted to the central electronic module (CEM) which unlocks the other doors, depending on the system settings. The settings are:
- total unlocking
- selective unlocking.
In order for the keyless vehicle module (KVM) to activate the quick lock function, the handles must be pulled out far enough to close the switch in the lock unit.
If the handle on the boot lid is affected, a similar procedure as above takes place. The difference is that only the outer antenna in the boot lid is activated to check the remote key.
If the setting for selective unlocking is selected, only the boot lid is unlocked and opened.
If the function for general unlocking is selected, the side doors also unlock when the switch on the boot lid is activated.

Passive starting
Passive start can be initiated in different ways. The system receives an indication that the vehicle is about to be started when one of the following occurs:
- contact breaker by starter button closes when the button is pushed
- a signal is received from the central electronic module (CEM) indicating that the brake pedal has been pressed (automatic transmissions)
- clutch switch (manual gearboxes).
The brake or clutch pedal must be depressed in order for the vehicle to start. For further information about pre-start checks, see Design and Function, Immobilizer.
When a scan for a remote key begins, the internal antennas are activated and a request is transmitted. Keyless entry remote keys will reply in order, transmitting their identity number and codes. The keyless vehicle module (KVM) compares these codes with its own codes. As soon as a received code matches a programmed code, the remote key is validated and scanning will stop.
The keyless vehicle module (KVM) then sends an encrypted message to the central electronic module (CEM) that an approved remote key has been detected and validated. This validation takes a predetermined amount of time.
If the starter button is pressed, the central electronic module (CEM) transmits a message to the engine control module (ECM) to deactivate the system for the immobilizer, therefore allowing the engine to start. If the starter button is not pressed within a predefined time period, the remote key validation will expire. If the contact breaker by the starter button, or any of the contact breakers by the pedals are reactivated, the system will scan for remote keys again.

Passive remote key warning
Passive remote key warning alerts the driver that a validated remote key has been removed from the passenger compartment.
If a passive remote key has been validated and used to start the vehicle, the validation only applies until the vehicle is switched off. If the engine is running and a door is opened, the system will scan the passenger compartment for remote keys as soon as all doors are closed. If the remote key that was used to start the vehicle is not detected, a warning message will be displayed in the driver information module (DIM) and an audible signal heard. The system will scan for keys each time a door is opened and all doors are closed again or when the driver presses the READ button. The engine will not be switched off. However, the immobilizer system activates and blocks new start attempts as soon as the starter button is pressed in to switch off the engine.

Reminder for ignition position
To prevent inadvertently draining the vehicle's battery, an audible warning signal sounds if the driver's door is opened and the engine is not running and the vehicle's ignition is activated by the starter button. A message is shown in the display in the driver information module (DIM) about what corrective actions are needed to switch off the ignition completely. This is to prevent certain systems in the vehicle remaining active.