W203 Keyless Remote no RF - PeachParts Mercedes-Benz Forum

rrf · #1 06-10-2002, 05:36 AM

2001 C-class has consistent problem with both remotes when attempting to unlock doors from more than 2 meters (outside of direct IR range). Both remotes have been replaced with latest revision number, problem persists.

I have searched the site and have seen some snake-oil remedies "use your head as a transmitter", "Mercedes Remotes just don't work very far", and even a post saying that "all W203 have this problem". From reading other boards that is simply not a correct statement.

The key/system uses an IR component as well as a RF component, apparently the RF section at this particular car is not working. Everything else works perfectly: IR, All Open, Panic etc.

Does anyone know the solution for this "common" problem?

Thanks in advance

rrf · #2 06-10-2002, 08:33 PM

I can see that nobody really knows the answer. That's OK, because I have looked on several other boards and nobody knows there either.

Here are some facts:
Some W203's do have problems with their key transmitters, there was a bad batch and there is a specific service bulletin out re that. Some folks need the newer rev keys. I don't know the exact symptom of that prob. But I don't believe it is "just" RF that doesn't work.

When properly functioning the W203 keys will work from 30 feet easily, without even pointing at the car. No, you never need to use your "head as an antenna". and RF Interference is not an issue.

If the key is working "IR-only", then you have to point it like a TV remote control, directly at the doorhandle on The W203. A few feet max dist.

The RF problem I have is apparently quite rare, "Bruno" the fellow that is on this board "on an island somewhere, three days from a MB shop" is one of the few (certainly less than 5) other cases posted on Benz forums worldwide. No, my dealer's Star Diag System hasn't found it. But hopefully tomorrow they will find another part worth replacing. I am loosing faith. My MBZ Service Advisor actually mentioned "Sun Spots" once, Good God. But maybe it was the MBZ chassis assembler staring at the sun too long.

Gilly · #3 06-10-2002, 11:58 PM

Hi:
Sorry, I didn't see your post this morning, no time to look until now. Maybe I can clear a few things up, maybe not.
First, yes, this is a 2 part system, RF (radio frequency) and IR (Infra-red).
The RF is what works the central locking system. The range that I have noticed is about 30 feet or so for RF minimum.
The IR is only used for the convenience features (lower or raising of windows and sunroof). This is line-of-sight only, and has to be aimed at the small receiver on the front door handles or trunk. This is a safety feature, they want line of sight to make sure nothing or no one blocks the windows when raising. You can get out there maybe 10 to 15 feet for this to work, assuming good aim. There are a few things that can affect the IR. Because we humans can't pick up on IR light very well, it's hard to know exactly what the conditions are at the time for IR interference. In general, the range will be reduced in bright sun, and solar flares, not sunspots, can affect IR range. Some vehicle colors can also affect range, either the vehicle the system is being operated with or even another vehicle parked close by. The more metallic in the paint the more pronounced this is, especially silver. One method for testing for IR interference is to test when IR interference is least present: try using the convenience system at night and see if the range increases.
If the range of the RF is a problem, then i don't have much to offer. The keys are new, so the batteries are also. May be a problem with the vehicle itself, not the keys.
Gilly
ps: also on the RF system, possibly a window tint with metallic in it ie "polarized" tint, may also affect RF range, and also possibly "overspray" of a metallic color I suppose would be another possiblity. Try testing the RF system with the side windows rolled down. If your main complaint is IR reception, possibly wax, armor-all, etc on the outside IR receivers?

rrf · #4 06-11-2002, 04:21 AM

I agree, the RF section of the car has to be bad. It is worse than POOR RF reception, there is NO RF reception.

I have 4 keys that all work perfectly for all IR functions and all don't work for any RF function at any distance. I could put the key inside the car and it won't work, nor will it work right next to the car. Yes RF is totally out on the car. IN IR mode, all of the functions do work, every one. I doubt it could even be the RF antenna it has to be the RF receiver. Where is the fuse line for that?

FYI apparently my situation proves that the key's IR abilities totally back up all of the usual RF abilities, perhaps as a fail-safe.
Every function works even for me, only for me they all need "aiming" at the door.

Thx for your response.

Gilly · #5 06-11-2002, 06:55 AM

After today, I'm gone to Mercedes school for the rest of the week. i am interested in researching this, but won't be able to respond until next week.
Gilly

#6 06-11-2002, 09:42 AM

fro what its worth, the rf feature on my 99 E-class doesn't work at all either. the only way to operate the systems with the key is to stand within three or four feet of the car and point directly at the door. When I got the car one year ago, the range of operation was about 30 ft or so.
The car is going to the dealer on mon. for check engine/SRS light
problems, so i'll post the results of the ke issue for those who might be interested.
Steve

#7 06-11-2002, 12:50 PM

There is an upgrade on these keys. I just got two new keys about two months ago on a warranty campaign.

Take it to your dealer and they will fix you up.

Have a great day,

rrf · #8 06-11-2002, 02:53 PM

Yes, now we are talkin.
I believe it is a somewhat rare situation, but because it is possible to "live with it on IR-only" some folks may not be aware or not be squawking about it. Because it is not intermittent it should have a simple yet defineable fix.

Of course, if my dealer finds something I'll post it.

Thanks to all.

rrf · #9 06-14-2002, 03:38 AM

OK car has been in the shop for 2 days and the dealer called today. "We found the problem, it is the antenna amplifier, has a short. We will call you tomorrow."

Glad I have a loaner, even more glad they found the problem.
But, I'll be satisfied after I see it working.

I believe the antenna amplifier is likely, however I never really felt the radio reception was weak. The amp they refer to should effect the radio reception too. But I live in a metro area with generally good radio reception, so, we'll see.

daddiojiggy · #10 06-14-2002, 04:31 PM

my '95 s500 remote seems to act the way you're describing.i can't lock/unlock from the front of the vehichle,i have to get in the 'line of site' with the door handle reciever.it does work from 20-30 ft away or so but only when i point at the handle.can somebody out there tell me if mine should work without pointing at the handle or is my system working properly?thanks

Gilly · #11 06-14-2002, 09:49 PM

Yeah, the 95 is IR only.
Gilly

rrf · #12 06-15-2002, 03:37 AM

Replacing the "rear antenna amplifier" solved the Smartkey RF problem in my 2002 W203 C-class. This job requires access in the headliner area of the rear window. All tests well now.

Thanks everyone.

BruNo787 · #13 06-15-2002, 09:14 AM

Hello rrf!!!!!!!!

alas after months of waiting, i finally found someone with a similar problem! Could you possibly post the "rear antenna amplifier" part number????????? I dont live in the U.S., so your help would really mean alot. Did ur dealer have to replace the entire rear glass?????????? or was it just he amplifier, from what i know, the amplifier is glued on the glass. Thanks.

BTW, i have an email for you.