Remote Control

The remote control can be used to activate system functions at a range of up to approximately 20 meters. The basic functions of the remote control are:

• unlocking the vehicle
• locking the vehicle
• unlocking the trunk lid/tailgate
• activating the local lighting
• activating alarm functions
• for the C70: unlocking and locking the storage compartment and ski hatch.

Internally, the remote control consists of three sections:

• transponder
• function for remote control
• function for the keyless entry system, if applicable.

The transponder is a communication circuit in the head of the key. The transponder has a unique identification code which connects the key to the vehicle. The transponder is coded. This code must be learned by the central electronic module (CEM) before the key can be used to start the vehicle when the key is in the ignition switch. Once the transponder has been programmed for one vehicle, it cannot be programmed for another.

The remote control has a built-in communication circuit and a memory. A coded signal is sent when a button on the remote control is pressed. This signal is received by a remote keyless entry (RKE) receiver and is forwarded on to the keyless vehicle module (KVM). For the remote control to work with the system, a unique code in the remote control must be learned by the keyless vehicle module (KVM). This takes place during installation at the factory.

The keyless entry system is used for: 

• unlocking
• locking
• passive starting
• passive key warning.

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. This takes place during installation at the factory.

Normally two keys are programmed for the key on delivery. Additional keys can be added afterwards.

The remote control has a key blade which is normally retracted inside the remote control. The key blade can be used in emergency situations to unlock the driver's door. This does not disarm alarm functions however, so should only be used as a last resort to open the car.

The remote control has an integrated battery which is used when commands are sent to the system. This battery must be replaced regularly. 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 Receiver Module (RRX). The Central electronic module (CEM) 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. Reduced remote control range is also an indication that the battery charge is low.

1. If the ignition key is held in the same hand that is used to turn the starter, the ignition key may not be identified correctly. This will display an error message in the Driver Information Module (DIM). The vehicle will not start either. The vehicle will start, however, if the starter is turned to 0 and a new starting attempt is made. The fault will not generate a diagnostic trouble code. This fault is rare.
2. If a button on the remote control is pressed when the Keyless Vehicle Module (KVM) attempts to read the identity of the ignition key, the reading will fail. This is because the ignition key cannot not transmit and receive data at the same time (pressing a button on the remote control will mean the ignition key is engaged in transmitting a "normal" remote control command). This fault could occur if the key is kept in a pocket or bag and a button is pressed by mistake.
3. Due to increased external radiation, for example from TV/radio transmitters and mobile telephones, the signal from the remote control can on rare occasions be jammed. This is a rare fault but it can occur, especially in particular places where different external signals can impair transmitting and reception conditions. This is not only associated with keyless systems but can also affect different types of wireless communication.