mb-grr

Hi,
I own a Mercedes C220 W203 (2001). I own it for about a year now.

My car has strange issues with electronics. At several points in the last year I had issues with the car key. At first, the car wouldn't accept the key. I would try again and it would accept it. I thought it wasn't such a big deal at that time.

However, later on, strange things started happening. The car would lose power (all electronics, except engine, would "die" - wipers, radio, AC, ... engine working normally). And that would happen while driving! After a restart, it would go back normal.


Today, my key stopped working completely.My car is practically dead.
The car won't recoginze any of my 2 keys at all.

My electrican says it's a bad EIS. He says he checked the car with STAR diagnostics, and all three keys seem to be blocked. I have only 2 keys. The third key must be at one of the previous owners.

However, when reading this forum, I think it could be something else as well. Before this final failure, the front fan would frequently go into the high speed mode,even when car was not overheated (for example, I start the car in the morning and fan goes to high speed immediately), which I consider strange.


Can all this be due to bad EIS or something else is the problem?

Does anyone have any clue what might cause all these problems? I understand it's a difficult guess, but any clue is appreciated!

Thanks!

stephan.roodt

Hi sir, it will be between the EIS and the ECU, where as a constant full speed of the fan I read on the forums means a ECU is going bad.

Also make sure the inside of the key where the IR sensor is in the front is clean, that is the piece that pairs the key to the EIS.

Warm Regards

mb-grr

Thanks for your reply!

I doubt it has something to do with the key as the problem occurs with both keys.
Before the yesterday's total failure, one was functioning ok 99% of time, and the second one was functioning 50% of time ( it depends on which side it was inserted - one side constantly fails to function on the second key).

I went to my mechanic / electrician yesterday to check it.
He turned off the car and then tried to push the key into the EIS and then bounce it up and down when the key was inserted. After that, both keys failed to function and the car was completely dead. It is very strange. Is it possible that such a simple action can break the EIS so easily?


Regarding the fan thing, I am to going to just hope it's not due to ECU, as if I have to buy both EIS and ECU, this will become the most expensive car to maintain in the history )

Another electrician is going to check the EIS tomorrow. Any input is appreciated.

Glyn M Ruck

The fact that both keys are problematic leads one to think that the problem is likely ESL or EIS or both. Check keys for any loose components on their boards. It has nothing to do with key batteries. They are inductively energised by the EIS.

https://mbworld.org/forums/c-class-w...t-process.html

A star will be crucial in diagnosing this.

mb-grr

It was the EIS (EZS).
I had it replaced.

Thank you all!

Glyn M Ruck

Sorry about that but pleased it's fixed! Thanks for reporting back.