Ali Yacoub

Hey so first off sorry for the lengthy post.

my car is not registering my key at all, if my key is inserted nothing changes, no lights come on, steering wheel doesn't unlock. when it did this, my key also stopped locking and unlocking my car.

some information:

if I put my key in my car, NOTHING HAPPENS.

if I put another key in my car, it says 'incorrect key'.

if I put my key in another Mercedes, it says 'incorrect key'.

I tried changing the battery on the key and checked all fuses.

thank you all so much.

Ali Yacoub

Forgot to mention that it’s a 2009 c300.

prktkljokr

This might help with some trouble shooting
http://www.mercedesmedic.com/mercedes-wont-start/

How good is your battery?

Ali Yacoub

battery is great! Got it checked and charged.

but the key will turn. It’s just like it never did. Ie no lights come on. Steering wheel won’t unlock etc.

prktkljokr

Im afraid to tell you but your EIS has failed, you pretty much have to remove the ignition and send it off with the key to have it repaired.
If you check "EIS Repair" on Ebay there are places you can send them and they repair and send back, generally a 24 hour turn around they are around $450 here in Aus so if you are in the US, it will be a quarter of what we pay.

Ali Yacoub

but would an EIS cause the car to not unlock/lock remotely?

prktkljokr

Here is a copy and paste from a Australian EIS repairers web site, It does say that it is a Immobiliser failure, I think that the unlock function still will go through the ignition system for Authorisation, It would be worth contacting one of these repairers in the country you live and ask the question

Mercedes W204 W212 C207 Steering Lock & EIS Repair

On the Mercedes 204 207 and 212 the most common immobiliser failure is caused by the steering lock and occasionally the Ignition switch. When either of these components fail it causes the vehicle to not start (no crank) and no dash light when turning the key. We provide a full rebuild on your steering lock and repair a common fault with the ignition switch regardless of whether or not it has failed yet. This ESL / EIS rebuild service comes with a 12 month unlimited km warranty and is plug and play which means no expensive dealer programming or coding required. In most cases we can offer a 24 hour turnaround.

Common Symptoms:

Vehicle Won’t Start
No dash lights when turning the key
Key turns but won’t start
Steering wheel jammed in locked position
Steering lock can’t be heard when inserting key