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Home >> Volvo >> 2012 >> S60 R Design AWD L6-3.0L Turbo VIN 90 B6304T4 >> Repair and Diagnosis >> Accessories and Optional Equipment >> Antitheft and Alarm Systems >> Keyless Entry >> Description and Operation >> Keyless Vehicle Module (KVM) >> Design

Design






Design

Control module




The keyless vehicle module (KVM) is located behind the right-hand wheel arch in the cargo compartment. 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 key.
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 remote key.
The keyless vehicle module (KVM) is part of the immobilizer system. It works with the central electronic module (CEM) to check remote key identities. 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 the control module Programming and Relearning
The two control modules communicate over MS-CAN.
The keyless vehicle module (KVM) contains five power stages. 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.

Internal antennas





There is a total of three internal antennas. The internal antennas are under the carpet:
- under the center panel
- between the center console and the rear seat
- in the cargo compartment.
The antennas allow the keyless vehicle module (KVM) to communicate with the passive remote key. The keyless vehicle module (KVM) activates the internal antennas in the event of any of the following:
- a signal is received from the switch by the start button (IAU) when it is pressed in
- an unlock sensor in the external door handle on any of the doors is affected
- a lock sensor in the external door handle on any of the doors is affected
- Lock or unlock button on tailgate is pressed in
- a request to check the remote key from the central electronic module (CEM).
The antennas are also activated when the vehicle is locked. This to deactivate any remote keys which are still in the vehicle. This is so that the vehicle cannot be passively started/unlocked by any remote keys still in the passenger compartment. The remote keys are reactivated when the vehicle is unlocked, started, or when the button for unlocking is pressed on a deactivated remote key.
The keyless vehicle module (KVM) checks the internal antennas every operating cycle if the vehicle speed is in excess of 20 km/h (12 mph).
The antennas are powered by the keyless vehicle module (KVM).

External antennas




The outer antennas are located in the door handles on the rear doors and in the luggage compartment.
The antennas make it possible for the Keyless vehicle module (KVM) to communicate using a remote key outside the vehicle.
The keyless vehicle module (KVM) activates one or more antennas when:
- the system receives a wake-up signal from any of the unlock sensors in the external door handles
- a lock sensor in any of the door handles is affected
- Lock button or unlock button on tailgate is pressed in
- a request to search for remote key is sent from Central electronic module (CEM).
The output of the antennas is adjusted during installation. This is so that there must be a valid remote key within a radius of approximately 1.5 meters from an active antenna for the system to function correctly.
The keyless vehicle module (KVM) checks the external antennas every operating cycle if the vehicle speed is in excess of 20 km/h (12 mph).
The antennas are powered by the keyless vehicle module (KVM).

Lock and unlock sensors




1 - Lock sensor
2 - Unlock sensor
Every external side door handle is equipped with two capacitive sensors. One sensor for locking and one for unlocking. A Capacitive sensor senses changes in its vicinity. The unlock sensor is located on the inside of the handle. The lock sensor is located on the handle's outside.
Keyless vehicle module (KVM) diagnoses the lock and unlock sensors after every driving cycle when the engine has been running and the vehicle has travelled at a speed above 7 km/h.
Lock and unlock sensors can also be diagnosed with diagnostic procedures under DIAGNOSTICS/KVM/Advanced/Checking door handle.

Ignition antenna unit (IAU)




For information, see: Design and Function - Electronic start inhibitor/Start lockout.

Start button (IAU)




For information, see: Design and Function - Electronic start inhibitor/Start lockout.

Remote keyless entry (TRX) receiver




Remote Keyless Entry (TRX) is installed on top of the headlining directly above the rear seat.
The receiver receives the signal, which comes from the remote key and forwards it to the Keyless vehicle module (KVM).
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 receiver's signal cable is directly connected to the keyless vehicle module (KVM).

The remote keyless entry (TRX) receiver has three different modes:
- normal mode
- passive mode.
- TPMS mode.
In normal mode, the receiver waits for a signal from the remote key when a button is pressed.
If the keyless vehicle module (KVM) receives an indication if someone is trying to open, lock, or start 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 three modes is the way in which the receiver communicates with the remote key.
When a remote key has been approved and has been used to start the vehicle, Central electronic module (CEM) ignores all messages that come from Remote Keyless Entry (TRX) as long as the engine is running.
The remote keyless entry (TRX) receiver is 30-supply powered via the central electronic module (CEM) and grounded in the body.

Remote key




The remote key has a different appearance depending on which equipment the vehicle has. The inner design also differs between the two models depending on whether it has functions for keyless entry or not. The remote key also contains a key blade. The key blade is normally retracted inside the remote key. 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 key are:
- Lock - to lock the vehicle
- Unlock - to unlock the vehicle
- A button to unlock the 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.
- Button for information about the vehicle's status. The button is only found on vehicle's with the keyless system.

Internally, the remote key consists of four sections:
- Transponder
- Circuit for remote key function
- Circuit for keyless functionality.
- One part with transmitter and receiver.
The transponder is used to identify the remote key for the immobilizer system when the remote key is inserted in the ignition. 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 key is used to lock and unlock the central locking and to activate the above functions. The circuits in the remote key which control the remote key 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 key 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 key is driven by two internal button batteries.
The batteries are used each time the remote key communicates with the system via the remote key function or the keyless entry function. The batteries are not used when communication occurs via the remote key's transponder when the remote key is inserted in the ignition.
The battery must be replaced regularly depending on how often the remote key is used. The remote key contains an internal voltmeter that reads the voltage of the internal battery. If the battery's voltage is too low, information about this is transmitted in the messages sent 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 shows a message that the voltage is too low. Another indication that the battery is deteriorating is that the range of the remote key starts to reduce.

Note! In certain cases malfunctions may occur in the system when communication between the keyless vehicle module (KVM) and the remote 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 remote key is held in the hand that is used to press the start button (IAU), remote 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 on another start attempt. The fault does not generate any diagnostic trouble codes. The fault is rare.
2. If a button on the remote key is pressed when remote key identification is carried out, reading off will fail. This means that the remote key cannot transmit and receive data at the same time (when a button is pressed on the remote key, the remote key is busy sending "normal" remote key commands). This fault may occur if the remote 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 and meters with remote reading, the signal from the remote key can, in some cases, be interrupted. 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 key is stored together with a mobile phone in a pocket or purse, it can happen that the mobile phone's signal blocks the remote key's signal to the vehicle. If the remote key'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 key'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 these symptoms occur, then no components are to be replaced. Instead, instruct the customer not to store the remote key together with a mobile phone. In order to achieve a flawless function, the remote key and mobile phone must be kept at least 10-15 cm apart.

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