Remote Control
The remote control is used to activate function in the system remotely. The basic functions of the remote control are:
- unlocking and locking the side doors
- unlocking the trunk lid/tailgate
- activating the local lighting
- activating alarm functions
- for the C70: unlocking and locking the storage compartment and ski hatch.
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 the remote control receiver and forwarded to the central electronic module (CEM). For the remote control to work with the system, a unique code in the remote control must be learned by the central electronic module (CEM). This takes place during installation at the factory.
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, in 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.
It has been shown that in some cases there is a system function fault when communication between the Remote Receiver Module (RRX) and the ignition key are affected for different reasons. The function fault is not due to any electrical fault and no diagnostic trouble codes (DTCs) are stored either.
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 places where different external signals can impair transmitting and reception conditions. This is not only associated with the central locking system but can also affect different types of wireless communication.