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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 mercedes clk 230 compressor will not respond at all to the

keys. We thought the... Show More
keys. We thought the batteries in the remote had gone so we replaced them but the next morning the car would not open or respond to the keys as if they just did not work. is the usual can you offer a solution
Submitted: 4 years ago.
Category: Mercedes
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replied 4 years ago.

Could you answer some questions please so I can get a better idea of what is going on:

Do you have more than one key - is the fault present with all keys?
Does the key not work in the ignition or is it just the central locking?

If it is just the central locking could you try pressing & holding a button on the key - a small red LED should flash on the key. Does this flash with all keys?
Also try aiming the keys at the drivers door handle directly at short range (there is an IR receiver here) - does the central locking work now?

If the key does not work in the ignition then has the vehicle battery been tested?

Best regards, Paul
Customer reply replied 4 years ago.


The battery is ok as the car alarm went off yesterday but the keys do not operate the central locking or the ignition. When I pointed the key at the car the indicators blinked but nothing else. The closest Merc dealership asked us to bring the car in not very helpful when you can't start it. Can keys be reprogrammed without the car

MB Paul, Mercedes Technician replied 4 years ago.

It is not possible to reprogram keys - the only thing you can do is to resyncronise them for the cantral locking side of things but this requires the key being able to turn in the ignition.

If the key does not work at all in the ignition then this is usually a key fault (less likely if you have 2 keys and both are not working) or a fault with the EIS (Electronic Ignition Switch). There are of course other possibilities but these are the most common causes.

Although it is not helpful when you cannot start the car to take it to the dealer it really will need to be checked with Mercedes STAR diagnostic tool - this has a test program to check the keys and the EIS system. If it is the EIS then this will also need coding on Mercedes STAR after replacement so it really does need to be at a dealer.

The car will need to be recovered to the dealer to check the system out - if you have had the car serviced at a Mercedes dealer last service then you are entitiled to Mercedes free breakdown service - Mobilo.

Best regards, Paul