Design

Design

Control module




The keyless vehicle module (KVM) is under the front left-hand seat. The control module controls and monitors the keyless entry system. The keyless vehicle module (KVM) uses the external and internal antennas to communicate with the remote control and to control the quick locks in the doors.
The keyless vehicle module (KVM) activates the internal or external antennas depending on the input signals and commands it receives. The control module also checks the identity of the key.
The keyless vehicle module (KVM) is part of the start inhibition system and works with the central electronic module (CEM) to check the key identity. For further information, see Design and Function, Immobilizer/Start inhibition.
The keyless vehicle module (KVM) must be programmed with various codes before it can function in the system. For further information, see: Downloading software and replacing control module Testing and Inspection
The two control modules communicate over the LS-CAN.
The keyless vehicle module (KVM) contains 4 relays. The control module uses these relays to select the antennas to be activated. See the table below:





Keyless vehicle module (KVM) is 30-supplied via the Central electronic module (CEM) and grounded in the body. The Keyless vehicle module (KVM) is always supplied with power as long as the vehicle is powered.

Note! During locking, the keyless vehicle module (KVM) only checks the quick lock motors in the doors. The other lock motors and the other functions in the central locking system are checked by the central electronic module (CEM).

Internal antennas




There is a total of three internal antennas. The internal antennas are under the carpet between the front seats, under the carpet above the center console in front of the rear seat and in the luggage compartment. The antennas allow the keyless vehicle module (KVM) to communicate with the passive key. The keyless vehicle module (KVM) activates the internal antennas in the event of any of the following:
- a signal is received from the key-in switch when the starter switch is pressed in
- a signal is received indicating that the brake pedal (automatic transmissions) or clutch pedal (manual gearboxes) is pressed
- a lock command is received from the remote control
- a lock button at one of the external door handles is pressed in
- the first switch in one of the external door handles is closed
- a request to check the key from the central electronic module (CEM).
The antennas are also activated when the vehicle is locked. This is to deactivate any keys which are still in the vehicle. This is so that the vehicle cannot be passively started by any keys still in the passenger compartment. A deactivated key is activated again when the vehicle is unlocked or when any of the lock buttons on the deactivated remote control are depressed.
The keyless vehicle module (KVM) checks the internal antennas every 5th operating cycle if the vehicle speed is in excess of 20 km/h.
The antennas are powered by the keyless vehicle module (KVM).

External antennas




The external antennas are mounted in the door handles (C30/C70 front doors, S40/V50 rear doors) and in the rear bumper. The antennas make it possible for Keyless vehicle module (KVM) to communicate with a key outside the vehicle.
The keyless vehicle module (KVM) activates one or more antennas when:
- the system receives a wake up signal from one of the unlocking switches in the door handles
- the system receives a wake-up signal from the switch on the tailgate
- one of the outer lock buttons is pressed in.
The keyless vehicle module (KVM) checks the external antennas every 5th operating cycle if the vehicle speed is in excess of 20 km/h.
The antennas are powered by the keyless vehicle module (KVM).

Switches affected by the external door handles




In addition to antennas (C30/C70 in front doors, S40/V50 in rear doors), the external door handles have two internal switches and a lock button. One switch is connected to the handle and is acted on via a linkage system when the handle is pulled outward. The second switch is affected when the lock button is pressed in. From the door handle, there is also a link arm to the quick-lock, where the link arm acts on a third switch inside the quick-lock when the handle is fully pulled out.
The first switch is closed when the handle is pulled out by 2-4 mm. When a switch is closed, an input on the keyless vehicle module (KVM) is grounded. The keyless vehicle module (KVM) wakes and activates the external antennas to scans for a valid key. This switch is closed for as long as the handles is pulled out.
Just before the handle is pulled out to its limit position, the switch in the quick lock is closed by the control arm from the door handle. When the switch closes, one of the inputs in the keyless vehicle module (KVM) is grounded.
This mechanical affect on the switch in the quick lock is one of the conditions for the keyless vehicle module (KVM) to activate the quick lock.
The switch connected to the lock button is closed when the lock button is pressed in. The switch instructs the keyless vehicle module (KVM) that the vehicle should be locked.

Key-in switch.




The key-in switch is inside the start control module (SCU). When the starter switch is pressed in, it indicates to several systems in the vehicle that the engine is about to be started. A 12V signal is transmitted to the keyless vehicle module (KVM) and central electronic module (CEM).
When the keyless vehicle module (KVM) receives a key-in signal, it activates one of the internal antennas to check that there is a valid key in the passenger compartment. The vehicle cannot be started until the key has been validated.
The start control module (SCU) is powered via the fusebox in the engine compartment.

Switch at the clutch pedal




This switch is only installed on vehicles with manual gearboxes.
The switch is installed together with the clutch pedal. In resting position the switch is open. It closes when the clutch pedal is pressed down by more than 90% of its entire stroke length. This ground one of the inputs on the keyless vehicle module (KVM). The keyless vehicle module (KVM) that informs the central electronic module (CEM) that a passive start has been initiated. The central electronic module (CEM) instructs the keyless vehicle module (KVM) to scan for a valid key.

Lock unit with quick lock functionality




The lock unit is installed in the rear of the doors. The lock unit has a quick lock function which is used to reduce the reaction time of the system. The lock unit has an integrated switch which is closed when the outer door handles are pulled out to their limit positions. The switch is mechanically connected to the exterior door handle by a control arm. This allows the keyless vehicle module (KVM) to activate the quick lock motors and open the door on which the handles was pulled out. The quick lock motor is activated after a key has been validated by the keyless vehicle module (KVM). The quick lock is mechanically connected to a catch in the standard lock mechanism at the striker plate on the car body. This means that when the handle is pulled out on a door, the door opens as soon as the keyless vehicle module (KVM) has validated the key. This reduces the reaction time of the system considerably.
The lock unit is powered by the keyless vehicle module (KVM).

Remote keyless entry (TRX) receiver




Remote Keyless Entry (TRX) is located up by the headlining to the left of the front lighting panel. The receiver receives the signal coming from the remote control or passive key and transmits it on to Keyless vehicle module (KVM) via serial communication (ISO).
The remote keyless entry (TRX) receiver has a logic which enables it to check that a correct message is received. All communication is decrypted in the keyless vehicle module (KVM).

The remote keyless entry (TRX) receiver has two different modes:
- normal mode
- passive mode.
In normal mode, the receiver waits for a signal from the remote control when a button is pressed.
If the keyless vehicle module (KVM) receives an indication from the door handle that someone is trying to open the vehicle using keyless entry, the keyless vehicle module (KVM) transmits a signal to the receiver to switch to passive mode for a short period of time. After this time, the receiver reverts to normal mode. The difference between these two modes is the way in which the receiver communicates with the key.
When a key has been approved and is used to start the vehicle, or if there is a key in the ignition switch, the keyless vehicle module (KVM) ignores all messages from the remote keyless entry (TRX) receiver. This prevents the status of the central locking system from changing if a button on the remote control is unintentionally pressed in.
Remote Keyless Entry (TRX) is supplied with voltage directly via 30-feed and is grounded in the A-pillar.

Remote control/Passive key




The remote control is identical in appearance in all markets. The differences are internal, depending on whether it has functionality for keyless entry or not. All remote controls also contain a key blade. The key blade is normally retracted inside the remote control. The blade is used as a standby option to open the vehicle should there be a fault in the system.

The buttons on the remote control are:
- Lock - to lock the vehicle
- Unlock - to unlock the vehicle
- A button to unlock the boot lid/luggage compartment lid
- A button to activate the vehicle lighting for 30 seconds
- A button to manually trigger the alarm if an alarm is installed.

Internally, the remote control consists of three sections:
- Transponder
- Circuit for remote control
- Circuit for keyless functionality.
The transponder is used so that the immobilizer system can identify the key when it is inserted in the ignition switch. The transponder contains a unique code. The central electronic module (CEM) must be programmed with the transponder code before the vehicle can be started.
The circuit for remote control is used to lock and unlock the central locking and to activate the above functions. The circuits in the remote control which control the remote control functionality are coded. These codes must be programmed into the keyless vehicle module (KVM) for communication to work.

The circuit for keyless functionality is used for:
- Unlocking
- Locking
- Passive starting
The circuits in the remote control which control the function for the keyless entry system are coded. The keyless vehicle module (KVM) must learn these codes for communication to function.
The remote control is powered by an internal button battery. The battery is used each time a key needs to communicate with the system via the remote control or keyless entry function. The battery is not used during communication with the key transponder when the key is in the ignition switch. The battery must be replaced at regular intervals depending on how often the remote control is used. The remote control contains an internal voltmeter that measures the voltage of the internal battery. If the battery voltage is low, this information is transmitted in the messages transmitted to the Remote Keyless Entry (TRX). The Keyless vehicle module (KVM) receives this information and transmits a message via the CAN network to the Driver information module (DIM), which, such cases, displays a message that the voltage for the remote control is low.

Note! In certain cases malfunctions may occur in the system when communication between the keyless vehicle module (KVM) and the ignition key is interrupted for different reasons. These malfunctions are not due to any electrical faults and do not generate any diagnostic trouble codes (DTCs).

1. If the ignition key is held in the hand that is used to turn the starter switch, the ignition key identification can fail. This results in a message being shown in the driver information module (DIM). The vehicle will not start either. However, the vehicle will start if the starter switch is turned to position 0 and another start attempt made. The fault does not generate any diagnostic trouble codes (DTCs). The fault is rare.
2. If a button on the remote control is pressed when the keyless vehicle module (KVM) attempts to read out the identity of the ignition key, reading off will fail. This means that the ignition key cannot transmit and receive data at the same time (when a button is pressed on the remote control, the ignition key is busy sending "normal" remote control commands). This fault may occur if the key is in a pocket or bag and a button has been pressed by mistake.
3. Due to increased ambient radiation, for example, from TV/radio transmitters and mobile phones, the signal from the remote control can, in some cases, be interrupted. This is rare but can happen. In many cases this occurs in certain locations, where different outside signals make transmission and reception conditions unfavorable. This affects not only keyless vehicle systems but all types of wireless communication.
4. If the remote control is stored together with a mobile phone in a pocket or purse, it can happen that the mobile phone's signal blocks the remote control's signal to the vehicle. If the remote control's signal to the vehicle is blocked and at the same time the customer tries to open the door by pulling the handle, the feature will not work. The same applies if the remote control's signal is blocked and at the same time the customer tries to unlock the vehicle by pressing the button on the door handle. If this symptom occurs, then no components are to be replaced. Instead, instruct the customer not to store the remote control together with a mobile phone. In order to achieve a flawless function, the remote control and mobile phone must be kept at least 10-15 cm apart.