The card does not lock or unlock the doors.

Symptoms

["Card battery is flat: Replace the battery. You can still lock/unlock and start using the emergency key/procedure.", "Use of appliances on same frequency (mobile phone): Stop using the devices or use the key.", "Vehicle in high electromagnetic radiation zone / Vehicle battery flat: Use the key built into the card.", "Desynchronisation of the card: Unlock the driver’s door by inserting the key, then place the card in the placement area and press the START button to synchronise."]