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MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 4317
Experience:  Mercedes Benz Qualified Diagnostic Technician
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My main key which operates lock/unlock, boot opening and central

Customer Question

My main key which operates lock/unlock, boot opening and central locking,on C250 turbodiesel, 1997, no longer operates the systems. Had key checked and it is sending relevant signals without activation. The flat plastic non battery spare will start the car. New batteries in remote make no difference
Submitted: 4 years ago.
Category: Mercedes
Expert:  MB Paul replied 4 years ago.

does the key that is faulty work in the ignition to start the car? Is it just the central locking that is not working?

Best regards, Paul
Customer: replied 4 years ago.

No, it operates nothing. It has been checked against a scanner for reading key fobs and been looked at via camera to see infrared signal operation. New batteries in it

Expert:  MB Paul replied 4 years ago.

If it does not work in the ignition and you have the flat emergency key that does work then the key that does not work is faulty.

Although you may have had the key checked in a key reader these only check that the key is sending a signal - they cannot say if the key is sending a good data signal that the car needs.

Once the key stops working in the ignition there is no way to resyncronise the key to get it working.

The fact that you have another key that works proves that the electronic ignition switch is working ok.

You will need a new key from a dealer which comes programmed to your vehicle.

Best regards, Paul