2008 MB C300 Will not start

In MB, the ignition key is inserted into a component called EZS which is basically an ignition key control unit which also doubles as an immobilzer control unit. E ngine control unit, EZS, transmission control unit and electronic steering lock control unit are all part of the immobiliser system. Based on your symptoms with respect to shifting, steering and starting I guess the issue is with the ignition key control unit. Start checking the fuse. Connect the scanner and read the actual values. There are CAN messages from EZS to other control units which will give a hint. Also read the DTCs

I just repaired the identical car, the ignition does not come on and the wheels are locked and it sets steering column mechanical fault codes.

This means the solenoid that locks the column to stop the wheel turning is faulty, after it receives the unlock command from the electronic ignition switch it tells the ignition switch it is unlocked and then the ignition switch enables the ignition.

Mercedes won't sell these parts to anyone they say they are security items and you have to pay the dealer to install and code the modules.(Completely illegal!)

I found a company that if you send them the column and electronic ignition switch they remove the faulty solenoid and fit an emulator and program everything to work upon installation. You have to clear all the fault codes after. No more lock problem.

I'm not a mechanic nor claim to be Benz expert.. so just a suggestion if it helps in anyway.

I had issue 2-3 years ago starting my 2008 C300 after car battery replacement (from AutoZone). Somehow, I got it started few times, but at one point it did not start and I had to call in AAA. I initially thought it was battery related issue, but the AAA tech use to work for Benz Services got my car started in 10 seconds. He told me the car was in "Security Lockdown". He recommended following steps in order. (Note: Try Procedure 2 only if first one doesn't work.)

To unlock the security -

Procedure 1:

(1) Unlock the car, (2) Turn the key all the way without starting the car (3) Let the mirrors open up and everything to reset (~ 10 seconds) -- Should do this every time! (4) Start the car

Procedure 2:

If above doesn't work, here's a keyless entry option on the key:

(1) Press Unlock (2) Lock (3) Unlock (4) Lock (5) Lock (6) Unlock (7) Follow Procedure 1 steps above

I was told the Procedure 1 should be best practice for every day use as well!

Same issue happened to me 3 weeks ago after my car was sitting in driveway for 3 weeks. I searched internet for couple days trying to recall these steps, but could not find it anywhere! Luckily, I had documented above step and emailed it to myself.

Please spread this steps in other posts as I've read about similar symptoms I had reported. Again, it may not solve the ESI or other issues, but this is 10 second steps that may save lot of money and headache for people so please do pass it around.

Thanks

These are the two most common problems with the C-Class. Bad EIS or

Failed Ignition Switch.

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This guide explains how to fix the ignition switch.