rwolak

2012 E350. One of my two key fobs will not start the car. It locks/unlocks doors fine, opens the trunk fine. However, it won't start the car. No starter clicks, just dead silence. I have checked the infrared light is functioning. Have changed batteries a few times. Still dead silence. I do have a second remote that works fine.

Any ideas or suggestions?

slovcan

Probably a dealer visit to reprogram the immobilizer chip in it. Or whatever is in there that identifies it to the car.

cetialpha5

What's the voltage of the batteries when you change them? Do you have a volt meter? Lots of dead batteries out there sold as new but they've been on the shelf too long. When you put it into the ignition does it turn all the way? You could take out the battery and try some electrical contact cleaner if you've checked the battery voltage and it's good. Or get a tile/apple airtag for your other good key so you don't lose that one. A new key is rather pricey.

rwolak

Voltage on all batteries used was 3+ volts. Even did the electrical contact cleaner, still no change. Strange thing is I used the car yesterday, no problems. Parked it overnight and the on fob wouldn't start it. Everyother function on the fob worked. Gotta be something in the fob since my other one works fine.

cetialpha5

Then it just sounds like a bad fob. It's usually either a bad fob or a problem with the electronic ignition. It's worse if it's the electronic ignition. Do you have keyless go?

rwolak

No keyless go. Doubt if it’s a bad ignition.
My other key works fine. Can these keys loose programming?

juanmor40

These keys are not re-programmable, i.e. if it lost the programming you can consider it gone.

However, these keys use induction, i.e. do not require battery to communicate with the ignition. You can take the batteries from your working key fob and it will still start your car. Batteries are opening the doors, and communicate with keyless go.

Can the be repaired? Not an expert on it. Did your keyfob fall on the ground, or got wet. If the inductive coil inside got damage, the key is a paper weight. In the meantime, careful with the working key.

konigstiger

Yes. Also, internal board can fail.

rwolak

Thanks for all the replies. A friend, who is a locksmith, has programmed many blank MB fobs. He’s going to take a look and see if there’s something I’m missing. Worse that can happen is I get a new fob.

M_patton

I have a c300 that had same problem
it was the ESL
I am positive it’s a common issue with that W204
here is a link to issue

https://www.benzworld.org/threads/co...thers.3046041/

benidB

another user just posted a similar problem
https://mbworld.org/forums/e-class-w...nk-no-aux.html

if no light comes up in the dash when you turn the keys, its likely the esl is broken. Check the link, I posted some other threads there that you can read..

konigstiger

Only key malfunctions.