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Mike, Mercedes Technician
Category: Mercedes
Satisfied Customers: 39198
Experience:  Tech Expert
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I have Mercedes C Class 2007 and the elctonic key occasioanlly

Customer Question

I have Mercedes C Class 2007 and the elctonic key occasioanlly fails to 'start' the car. I remove the key turn it round and it usually works. I keep my spare key just in case. Last week both keys failed to start the car. I sent one key away to be tested and apparently the key is fiine (still waiting for it's return). Sort of implies it is the receiver for the key or (similar).
Like to find someone with appropriate knowledge (I live in Southampton) to resolve what could be a potentially real problem
Submitted: 10 months ago.
Category: Mercedes
Expert:  Mike replied 10 months ago.
Hello and Welcome -
My name is ***** *****
It certainly does sound as though you have narrowed it down to a key receiver issue / fault - and this is usually when this happens - the part that the key slots into as faulty.
I would recommend really though that you have that tested properly - this is done with a plug in test - If you have a Independent MB garage near you - that would be cheaper than a MB dealer - but if not, you will need to use the local dealer for this - as not many small type garages have the right diag equipment for this particular test.
Your local Yellow Pages - or will easily locate a garage or MB dealer near you if you go that site ( or book )..
Basically what tends to happen with these are two faults - either the contacts inside the unit wear too much too contact / work - or, they fail electronically internally. Im afraid there is no real suitable way of repair on these - the only answer is to have the unit replaced when this occurs.
But again - the advise has to be to have it properly plugged in to a suitable diagnostic machine - just in case it is actually a fault in some other part of the system - such as the control module / computer that has overall control of the ign.. You wouldn't want to replace the key receiver and then to find it wasn't that --
While Im in the UK Im not in your area but I did do a search for you for an MB specialist - and this one came follows -
Let me know how you go..and / or let me know if you need anything further on this.. I will be back on later today if you need me.
~>>~~>>~ Meanwhile now at this point- Please do click on the "Exc / Ok rating" for me at this time.. "Thank you" in advance for that .
.. Note that you can get back to me anytime at all after doing the rating - it doesn't close you out --
Best Rgds, MIKE
Customer: replied 10 months ago.
Mike - thanks.
As you state I have done a lot to track this down.
(MB Main Dealership - useless - £83 for a test then no idea what until they do the test and ages on the phone)
In the meantime I got hold of the mbsofsouthampton who still reckon it probably a key problem but do have the equipment test thoroughly (which they say main dealer doesn't have).
I certainly have a good degree of confidence they will get to the cause of the problem
Customer: replied 10 months ago.
Looks like a dodgy 'wheel locking' mechanism which certainly needs replacing and may well be the entire problem.
The key failed at the garage just as I was about to leave and confirmed the initial thoughts

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