Long read but trying to be as detailed as possible here.

2003 Cl-500 (W215)

About a Year ago to date, my CL started to lose Range in the RF transmitter. I had to stand closer and closer to the car to get it to work until eventually I had to stand damn near ON the car to get in. As of July the RF no longer worked and I can only get in with the IR on the door or the metal key blade. Checked the fuses, didn't see a problem there and gave up considering my warranty company wont fix "Security" related issues and that is tied into the security system.

Starting in August of 09, the IR no longer works. Sometimes if I shake it enough or bang it on the floor, it will unlock, but it would persistently get worse until it died that month. I had too much going on and as long as it drove I didn't care at the moment. I parked the car at the end of September or beginning of October and kept it at home in preparation for winter. I was planning on starting it weekly but due to unfortunate family circumstances, the car was the last thing on my mind and I left it as it sat.

I came back to start it one day in November and it would not start. I talked to someone at the dealership and they said to hit it on the ground a bit and i would work. Sure enough, it did. But the second time I went to start it, no matter how hard I would hit..... No Workie. This began to frustrate me and it went months without starting it. I decided to plug the battery in and keep it charged in case that was the issue which it was not, and still no recognition.

And now, here it sits in Feb with No reaction to my key. I couldn't find my spare key which also didn't work from past testing, so I decided to buy a New key. I just received my new key today and it neither Locks/Unlocks the car nor does it start it. Nothing. I left it in the ignition for over 6 hours and still, no reaction.

Side note: the key doesn't Turn, Light up my Dash, Or ANYTHING. Car just doesn't recognize. The temperatures here in Cleveland are VERY cold and I feel it may be a problem or a cause, but for BOTH functions to completely stop, hard to swallow that.

I know the Key fob controls the two functions Separately. From reading this, is there anything you can tell me that I'm forgetting to try here? I will be back online in the morning when I get to work so I will check it then. Goodnight for now, and I hope someone is familiar with this issue.

ALi

 

Long Story Short, My keys don't work, for either Lock/Unlock or Starting Functions.

ALi

 

I don't have any direct experience with your model but I believe it shares the same key mechanism with many models. Did you change the battery in the key fob? The banging it to make it works is an old trick to agitate the battery chemicals enough to get a pulse. Did you order the key from a dealer? If yes to both questions then I'm guessing your EIS unit is bad. The thing you plug the key into. There have been several posts by people with the same symptoms that showed up when outside temperature dropped. Expensive and only someone with SDS can accomplish (dealer).

 

New Keys, And new Batteries in the old key as well.

Also, what does my EIS have to do with my central locking, unlocking. That's where the mystery comes in. Car locks and unlocked when the Metal key is turned in the door, just not by command of the key fob.

ALi

 

You have to find out from the dealer to see if they ordered a duplicate key or a seperate key. because you only have 8 keys that you go thru.

 

And second does your car have keyless GO?

 

Key is not a replacement, so I assume it's a duplicate maybe? Either way, It was sitting in the ignition for 6 hours. He told me it should be ready to go.

And no keyless go.

ALi

 

If you ordered it from the dealer you have to request from them to give you the key track # charts and they have to tell you what they ordered. From factory you are given 2 keys # 1 and # 2 then if you want to order new keys you always order duplicate # 1 or # 2 if they ordered you a different # key that is why you are sitting in the car so long waiting for the eis to register the key.

 

what is the part # of the key that they ordered you?

 

Mystery for me too Ali. Evidently it looks at the key code for authentication before it unlocks? Here's a link to someone having the same problem:
https://mbworld.org/forums/c-class-w...t-enginne.html

 

I don't have the Key on me but I can get it later, how do I find it on the paper/key.

Just posted there, no solution yet.

ALi

 

The part # that is on your sales invoice.
Let me know what the part # is.

 

A 211 766 77 06 9999

is that it?

I don't have my sales receipt on me but that's off the packaging.

ALi

 

Unless he specifically requested a dupe track they would not have ordered it. He most likely has a next available key which should not require any synchronization. It sounds like the car has no power still does the cabin lighting illuminate when you open the door? Have you tried calling roadside and having them replace the battery instead of using the charger? The RF and IR are different things even if the EIS is blown you should still be able to open the doors. Roadside is free and they send factory trained techs that will give you more insight on the issue. 800 FOR MERC Also the bag that came with the key will say if it's a dupe or next available. Also the car being key less go is irrelevant since it's a 2003 and the IR keys do not contain the KG function because they use the credit card. Good luck!

 

Full power throughout the car, all lights are lit, headlights, navi, everything works. Roadside tried doing the same but the car has full power and all they suggested was to tow it in, problem is I know there will be many issues with how low it is including my front lip spoiler being on as well.

ALi

 

Weather is better, car started up!

ALi

 

Great!! Your EIS is probably bad.

 

I'm sorry but I may object. Check this....

So I unplugged the battery for a fews days(5-7 actually). I popped it back on the day it started but it didn't work right away. I gave it an hour to warm up in the sun as it was just coming up. Started right up.

Now, I tried starting it today and it was 46 degrees, started right up. WEIRD part is that my RF lock/unlock features now work from my garage to the neighbors garage door across the street. It hasn't done that in at least 8 months or more.

Any ideas? New key still wont work btw.

ALi

 

Weird, be thankful it works The reason I guessed EIS is several people on the forum had the identical symptoms as you.....key didn't work when it got real cold, started working as it warmed up..... and it turned out to be the EIS.