Hi all

E300D - W210 - 1996
Single button keyfob with flip out key (only 1 fob / key), IR receiver unit in rear view mirror with red & green LED's. No LED's in door handles.

Doors lock & unlock OK using the key fob. Turn key in ignition to start engine, engine cranks OK, but no start. Red & green LED's flash alternately during cranking & for about 30 seconds whilst ignition is switched on.

I have replaced fob batteries & re-syncro key fob according to owners manual numerous times, but no luck. I have tried a number of the other suggestions I have found on various forums too, but nothing seems to work.

Anyone have any ideas as to what the fault is & how to cure it?

Cheers
Garry

__________________
The KISS principle (so who's gonna tell MB?)

OK guys, I disconnected the car battery & removed the key batteries overnight in an effort to clear any spurious codes that may have been there. This did nothing. I again re-syncronised the key, again same problem.
I took the key apart & found it has a small Philips transponder chip (13x5x2mm) just behind the infra red emitter LED. This is not connected to the batteries or circuit board in any way, so I am assuming it works the same as most other cars & simply sends its static I.D. to the ignition lock pick up coil when the ignition is switched on. Also, the only place to get a new key is MB, whereas most other manufacturers keys can be bought & programmed from any good locksmiths if you have a working key, or programmed via the car ignition switch. This would mean there is no facility in the car to reprogram or resync the chip, so the re-sync process does nothing for the chip / immobiliser, but simply aligns the infra red signal between the key fob & the central locking / alarm unit. OR IN OTHER WORDS, if you were able to totally remove the alarm / central locking system, the immobiliser would still work, as it is a separate circuit / system.
I cant work out why no one wants to program a key. There are keys in locksmiths around here with a flat bladed key & transponders built in that would fit, even though they have no infra red. Perhaps MB have some kind of 'patent', preventing 3rd parties from reproducing their systems.
Am I correct or am I barking right up the wrong tree?

__________________
The KISS principle (so who's gonna tell MB?)