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2003 c240 Smart key

Old Sep 2, 2013 | 11:47 AM
  #1  
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2003 mercedes c240
2003 c240 Smart key

Hello All!
I have a 2003 c240 the smart key will turn the engine on but wont lock/unlock any thing in the car. the key itself is in bad shape, has holes on the outer case/cover on each of the three locking clicks exposing somewhat the chip inside and at this point im not sure if the inner chip is destroyed or just the case or even battery? The smart key itself doesnt have a small light indicating battery life so i have no idea if its an issue or not, i did go to autozone to check it out and the guy did a quick test to the battery to see if thats the issue, but it wasnt as the receiver did light. Anyhow, what is the issue can someone help me please?
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Old Sep 2, 2013 | 01:34 PM
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If the key was destroyed it would most likely not turn on the car.

Aim the key at the door handle and the rear glass window. See if it unlocks/locks the vehicle
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Old Sep 2, 2013 | 01:41 PM
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2003 mercedes c240
I tried just now, theres no response what so ever, and looking at the lock button i can tell its been destroyed from the chip, looking at the trunk or the unlock buttons theyre intact and seem to click normally although no response either. The car ignites normally im wondering if its low to non battery or if the chip needs to be replaced?
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Old Sep 2, 2013 | 02:40 PM
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If the chip needed to be replaced you couldn't start your car. Sounds like it could simply be the battery.
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Old Sep 2, 2013 | 04:25 PM
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If you have holes on the buttons, the case is toast. Point the end of your key at your phone camera. Press each button. There should be a brief flash of light at each push. If not, the whole key is done.

The EIS in the dash does not use the battery in the key to start the car. You can start with the battery removed. The RF system is the one that does not work to lock and unlock the car without a healthy battery.

Some locksmiths can get the keys now and set them up on your system. Ask the AAA for a referral.
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Old Sep 2, 2013 | 05:37 PM
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2002 c240
There are three total radios built into the motherboard on the key fob. Be glad your key starts the car, the rest is able to be worked around with your manual key to lock the doors. You can code the door locks yourself using a spare key fob on many of the Mercedes so perhaps this one as well which means a $20 fob off ebay would solve your issues, you'd just have two fobs. One for locks and one for engine.
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Old Sep 3, 2013 | 01:15 PM
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2003 mercedes c240
The key itself has no light to indicate if its working but i took the key to autozone they detected some battery in it since it lit up in some buttons, but the car still doesnt respond, im afraid the chip where the lock and unlock are messed up while the area where the ignition starts is ok? i asked lots of place and no one knows anything if anyone could recommend a place besides mercedes dealership i really appreciate
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Old Sep 3, 2013 | 01:16 PM
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2003 mercedes c240
If i can do it myself too i dont mind is it easy? all the ebay fobs are shells only which might not solve my problem?
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Old Sep 3, 2013 | 01:25 PM
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You'll have to just put on your big boy pants and buy a new key at the dealership. No other way around it.

Do ask several local dealerships, if you have a choice. I was able to save $30 something on a new key by asking around.
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