Newbie here, but I have an '02 C240 in which the smart key is not working when I put it into the ignition. I recently purchased a new key and it does not work either. Both old and new keys will unlock the doors and such, but I can't turn the key to start the engine. Everything is locked up on the car (ie steering wheel shifter etc.) so my question is how do I get my car towed to a dealer that is about at 50 miles away when I can't put the car into neutral..? Thanks in advance for any feedback..

 

You do not have drive authorization. This is security measure against theft.
It is not possible to turn the key immediately after inserting it into the electronic ignition switch, because it is first necessary for the locking bolt to be pulled out of the locking ring and secured. Only then does the electronic ignition switch receive the release signal.
This delay requires approx. 0.5 sec.
If the ESL (electric steering lock) does not return a release signal to the EIS (electronic ignition switch), then the key can not be turned.
Mutual infrared communication is accomplished between the remote control key and EIS. The remote control key identifies itself to the EIS. After checking, this identification is passed on to the ESC. After checking the identification the ESC unlocks the steering and then releases the EIS to turn the key.
When you insert the remote key to the ignition switch you should hear audio signal. If you do not hear audio signal there is no way that you can turn the key and start the engine.
Problem is control modul does not recognize your key. Same apply for new key.
I had the same problem 3 times and I found solution playing with the key and drivers door.
Try this:
1. close all doors,
2. insert the key in ignition switch; you should hear audio signal. if not, pull out the key and open and close drivers door; insert the key in ignition again. Repeat this 3-4 times.
Remember, for each try you need to open and close drivers door. IT WORKED FOR ME.
Good luck.

 

Hi I own a mb 2000 c240;around 7:10hrs my car could not start so I figured battery problem, I recharge the battery for about an hour(The original battery Varta battary 12V 100Ah 760A).The car started then the following day it could not start. Again I took the battery for a 4hrs recharge the car started and I was able to use it for three days;on the fourth day in the morning it could not start. I've bought a new exide battery 12V 100Ah 860A it can't start any Ideas what the problem could be

 

1st try a different key. Could be a crank sensor also could be fuel sending units. Sending units are common.

 

I have an CLK350 2009 and weird starting problem. It takes 2, 3 ,4 seconds before engine starts. My mechanic is very good and he told me to check every time when I insert the key if I hear a sound and if I did make sure that the steering wheel is unlocked. If I hear the sound and the steering wheel is still locked then I got a bad ESL (Electronic Steering Lock) unit right on the steering column. I checked and I heard the sound of the ESL motor unlocking the steering wheel and physically tested to see that the wheel is unlocked by moving it left/right. However I still would get the delay. Also if the delay is 4-5 seconds before it starts I get ESP inoperative and right after that I get the Red screen with the battery symbol. I told this to my mechanic and I left the car so he can figure what is causing this. He called me back and said that there is a problem between the locking system and the ECM (main computer) and I need to replace the ECM. He said that he does see this often because the ECM(Computer) is mounted on top of the engine and since I am in Florida and it is hot plus the engine heat damages the computer as we all know computer do not like heat. He told me that on some models of BMW they have moved the location of the ECM next to the firewall and applying air conditioned air to the ECM. Anyway they do not make anymore ECM units so he hat to get a reconditioned unit with 12 month warranty. With the part and labor cost me $1600 and now the car works great again. I think Mercedes Benz is crazy to place a computer unit on top of engine. I think there should be a recall on this issue.

 

What also can happen is the the ESL (Steering lock) has lost its carbon brushes. Hitting the steering column may help in starting once more, then drive home or stealership. Home if you can DIY as China sell that ESL motor for US$5 and if you are a Youtube mechanic, you can pull out the ESL and insert a new motor or pay $2,000 at the stealership. I messed up the ESL and had to send it to Australian ECU Repairs for $450 to get fixed.