RichardBr

I have a 2003 C270 cdi. A superb vehicle with high mileage. It has suddenly developed a central locking problem. If the car is locked via the remote it unlocks normally for a period of about 1 hour after locking. If left for longer than 1 hour car will not unlock. It goes into "sleep" mode and can only be opened with the little key

RBT252

Hi, I have a similar problem with my CL500. After around 8 hours, my key fob does not work and I need to use the blade key, as soon as I open the driver's door the key fob/central locking will work for another few hours before going back to sleep.
Did you ever find out what was wrong?

The CL500 has both radio and infrared signals from the key fob. I have noticed that after around 6 hours the radio signal seems to be put to sleep first, this means I need to get close to the car, around 6 ft for the infrared signal to open the car but after another couple of hours that goes to sleep too, meaning I need to use the blade key to open the door.