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Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: Mercedes
Satisfied Customers: 6223
Experience:  Owner at Carolina Auto Service & Sales , 20 years experience in Foreign & Domestic vehicles
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I have a C300 2008 model. I just tried to remove the

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Hi I have a C300 2008 model. I just tried to remove the mechanical key and after putting back remote does not work
JA: Is the key stripped or worn?
Customer: No. Key is in good shape
JA: Are you fixing your C300 yourself? What have you tried so far?
Customer: Tried to open the door with mechanical key. Tried to start the car with remote smart key. No reaction.
JA: Anything else you want the mechanic to know before I connect you?
Customer: No, that is all

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Customer: replied 10 months ago.
Okay thanks
Customer: replied 10 months ago.
I noticed that infrared light does not come on in the remote when I looked through mobile camera
Customer: replied 10 months ago.
Red LED. Comes on when I press the remote

Hey how are you ,I will Try to Help you with This Issue

are in Switzerland ? my screen shows it , wow, i went to Verbie when I was kid skiing ?

question is our 12 volt battery holding 12 volts , a weak battery will make the ignition not release and loose sync with car security module

we also need to check the remote battery ?

any security light blinking on dash

If you do not mind me asking are you looking for the most possible causes and taking it to a repair shop or you are repairing it yourself and you need step by step instructions
Please Let Me Know
Thank You
Chad Farhat
ASE Certified Technician

This here sound security system is triggered on

Customer: replied 10 months ago.
I will take it to repair shop after knowing possible cause
Customer: replied 10 months ago.
I am in Switzerland

There is a TSB ( technical service bulletin on the Transmitter

does the remote still starts the car but no function,like door trunk etc ?

Customer: replied 10 months ago.
Sound security system.How to fix this.?

You will need a Capable Factory scanner or equivalent to Read the Fault codes in the Modules needed and based on these faults we can pull up a Pin Point Troubleshoot and be Accurate ,If you get the Faults Read ,post them back here for me and I can Help You Further on it & we be Accurate

But the most common are the transmitter or a hood ,trunk or door switch stuck open , Your next step is Dealer or a shop with Mercedes Star scanner to read anti theft modules faults and we can be accurate

what is the mileage on it now ?

Customer: replied 10 months ago.
No. Car does not start. Can’t open the door using remote. No lights on the panel when I put the key and rotate the ignitio

Security system is triggered

I see on my screen you ask for a call, not necessary here, and calls can only be initiated to u.s locations only , unfortunately not overseas , we can do skype ?

Customer: replied 10 months ago.
112000 km

at this mileage i doubt you have a major issue , this here could be simple battery in car low, or key transmitter battery or switch keep system from resetting

unless you forced that key and broke the ignition key cylinder ,does the key turning feel loose to you ?

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Thank You?Chad Farhat?ASE Certified Technician

Customer: replied 10 months ago.
In the remote LED comes ON when I press unlock or lock. But no response from the car

well the red light coming on is good, mean battery is okay in remote but we do not know if we lost syn with car receiver

and we do not know if the remote battery is weak

Customer: replied 10 months ago.
How do I ensure remote is fine?

Check hood switch ,,click on link to view

on 2008 ,you will need a scanner to correctly test ,battery wise and rf signal wise

they make it now days that you have to thru dealer when it comes to security

do you have a black casing key fob or silver color ?

Date: January 5, 2009

Order No.: S-B-80.00/53


Group: 80

MY- All, Models All

Replace Battery in Transmitter Key

In the event of complaints about the function of the vehicle key, first check for and remove any soil or grease from the battery or battery contacts using the lint-free cloth and alcohol.

To ensure faultless contact, do not touch the batteries on their contact sides.

pdf file ,click on link .

timing marks ,

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