gino1961

I have a 2002 C class sedan that I bought privately. One of the keys does not work and to replace, MB are asking for $700 Aus Dollars.

The faulty key seems to do everything correct, when I press any button the red led blinks. The infra red also works, when i look thru a digital camera, i can see the light flashes. Yet i cannot open the car or start the car.

Any ideas if this key can be repaired?

Thanks Heaps.

Gino

raymond g-

try polishing the IR lens

check the battery voltage, static as well as under load (report back)

the bad key does not belong to your car - previous owner purchased it off ebay (wild guess)

gino1961

Thank raymond for the quick response.

I will try and polish the IR lens.

It has passed thru my mind that it might not be the correct key, the metal key itself does open the car. The writing on the inside of the battery compartment : 315MHZ and the FCC ID, and the CAN numbers are identical. Is this the same on all keys?

thanks

gino

raymond g-

dont know . i know north american keys use different frequency than other countries.

another trick...but not possible for yours at this stage is to insert key into
ignition and turn to position 1 and let it sit for a bit while the interlock circuitry
interrogates the key. polish lens first.

unlocking car doors uses RF
open/close windows and roof uses IR
ignition uses passive induction and I think IR, too

http://edsoto.com/e320/w210/electrical.htm
(oops, that's for 210 but it's very possible your 203 of that year will be very similar. will try to check)

p.s. yeah it seems to be set up very similar to 210s *see attachment*

gino1961

Thanks Raymond, you have been of great help. Sounds like the second key does not belong to my car.

Can this key be reprogrammed to suit my vehicle?

raymond g-

not easily....very unlikely....extremely difficult....chinese hackers have been
selling something but it's not cost effective. all those smartkeys being sold
on Ebay are ripoffs. zero reprogramability.

I was able to get my chrome Smartkey for $60 US but that disappeared quickly
when MB USA found out about this loophole. now, it's about $2-300 US.

no, we can't help you because with MBUSA policy, must have car registration
and driver's license, blah blah...