Immobiliser - Engine non-start

[Chumneywarner]

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 this forum to, but nothing seems to work.

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

Cheers
Garry

 

[Ted]

used happen exactly the same on my w210
I would use the other key fob or the credit card key to start it, and then it would be okay for a few months.

 

[Dieselman]

THIS might help.

 

[Chumneywarner]

Hi Ted.
This is not an option for me, as I only have the one key.

Hi Dieselman,
I was going to buy a 2nd key for obvious reasons, but buying 2 is a bit much. I am going to try disconnecting the car battery overnight & give it a charge to make sure it is fully up. Hopefully this may reset the car systems. I am also going to take the batteries out of the remote overnight & replace with new for the same reason. I will then try a re-sync of the remote system & see what happens. I don't hold out much hope & think I'll be phoning my local MB stealership for either a new key or a diagnostic session . . . . OUCH!

Thanks
Garry

 

[BlackC55]

Go for the key. It is very likely to be the problem.

 

[dss]

help immobiliser on...

hi all,

this is very similar to what happend to me today.

C180 '97, press key fob and doors open but no beeping sound to say alarm is off also only green light flashes on door handle and rear view mirror.

attempt to start, but engine turning over but no fire...

i've also disconnected main battery and alarm go's off, but strangley it's audio level is very low.

i've also reversed the process by pressing the fob and doors lock but no beeping sound to activate the alarm.

i've changed the batteries on the fob, but to no avail..

it's almost like the batteries on the alarm system have died. is this possible??

the car is truley immobilised and i'm desparately stuck..pls help

thanx

 

[Dieselman]

That sounds more like an alarm fault or the siren dragging down the power. try disconnecting the siren.

 

[Chumneywarner]

Well guys, thanks for your input so far. As soon as I cure the problem & find out what the cure is, I'll let you all know.
Its a shame you can't disconnect the immobiliser to get yourself out of trouble, maybe something specific to the car & not generic, so not for the use of any thief & vagabond! Maybe a series of keypresses & ignition 'on/offs' like the re-sync sequence. I don't know, it just seems daft to me that the owner can't use his own car & this sounds like a common problem if you read the entries in the various clubs & forums on the internet.

 

[Chumneywarner]

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?