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

whoover

Did you lock and then unlock the driver's door with the physical key (not the remote)? I don't recall whether that's the documented resynch procedure, but that's what used to work for me on my W140. I think it was lock, unlock, and then start.

If nothing works, it's a control module and you'll need to have the agent fix it.

Chumneywarner

Hi Whoover,

No, I haven't tried that. It's not the re-sync proceedure quoted in my manual, but I'll give it a go. Never know your luck.

Thanks
Garry

Chumneywarner

OK, 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?

markweboz

My 1996 W210 E300 Diesel (UK Model) has the immobiliser problem. The red & green lights flash and it will not start. The fault clears after about 3 hours. Have done the reset procedure as per the manual. This has happened 5 times in the last 2 months. The MB agent is not helpful. The car was exported from the UK to Australia & they claim lack of service information. Can anyone please help? I would be happy to disconnect the immobilser if this is possible. Searches reveal references to the K40 relay module. Is it worth changing this?

Thanks valued forum members - this is driving me nuts.

max10

Hi sorry to bring up old thread but did you have any luck with the problem my red and green leds are both flashing when i unlock the car with the rc key
and will not start have replaced fob batterys but still not starting have also disconnected car battery any help appreciated

Max

markweboz

It turned out to be a fault in the wiring harness. Intermittent connection. Going fine now.

mahoskic

Can you tell me what harness had the problem?
i have the same issue, sometimes it runs all day but lately is is getting worse, like it stops running @ stop lights or making a turn.

Any direction you can point me in?

TMAllison

What year is yours?

Do your R/G lights flash alternately or simultaneously?

mahoskic

the flash red and green alternately before i try to start the car.

TMAllison

You didn't say what year you have. I'm assuming its a 96 with early version security system.

Alternating flashes means an unauthorized start attempt.

Sim flashes means the key battery is weak; the early security system used some key battery power in the security communications, later versions did not.

Try exiting the car and locking and unlocking the car using the blade key in drivers door. Then start and observe mirror lights.

markweboz

You asked where in the harness the fault was located. Can't help as it was fixed by a repair firm (not a merc dealer). The lights were flashing alternately. Car has been fine since the repair.

TMAllison

It would commonly be where the door lock wiring leaves the chassis and enters the doors.
****************

What year is it for the 3rd time?

I suspect you have two issues. One is key related and the other is shutting down the engine.

When the engine shuts down is it w/o warning, as if the key were turned off? That is usually an intermittent K40 relay inturrepting the power to the shut off valve on the side of the IP casuing it to close. Occassionally, it is a leaking oring behind the SOV.

The CPS is not the issue on a diesel as it mainly proivdes data for the tach (and some emissions sensors); it has nothing to do with timing like in a gasser.

mahoskic

Sorry it is a 1996 e300.
this car will shut down as if the key was turned off, it will not start back up and the green and red lights flash on the mirror.
i changed all the fuel lines and he shutoff valve and all the o rings.
i also noticed that sometimes the check engine light comes on or flashes, it goes out after a few hours.

TMAllison

Do this....When it is in no start mode, open the drivers window and the hood and then turn the key to POS 2. You should hear the click of the SOV opening on the side of the IP when the key is turned. No click = no start.

Typical problem is the K40 relay (front most relay in the computer box - takes 10 minutes to change), its circuit board develops minute cracks in the solder joints interrupting power. It replaced the OVP used in older models; feeds power to numerous devices including the security system. You can open it up and look for cracks with a magnifying glass; some folks have even repaired them. For ~$80 its not worth trying in my opinion.
http://www.detali.ru/cat/oem_mb2.asp...SGR=080&SGN=04
#056 2105400372

Occasionally the problem is a faulty SOV or a leaky oring behind it that causes the valve to partially or fully close. Yours is new, did you also replace the oring? Any leaks under the SOV?

Most commonly is the K40.

mahoskic

Went into the K40 Relay this morning.
I did not see any cracks but i heated up the joints, i ordered a new one anyway.
thanks for all the help i will let you know.

Hitless

An update on the subject. Resoldered the joints of the K40 relay board and the problem disappeared. It was the same issue with mine - the red and green were intermittently flashing and the car did not start... always in the most unpleasant situations. Now it’s fine. Thank you all for this valuable post.

Cheers

machinewbie

I have had problems with the immobilizer preventing me from starting the car as well. Seems to work fine when I leave the house but refuses to get me home. Red green flashing Grrrrr. Replaced FOB batteries, replaced FOB, replaced car battery. Every time It would work for a week or two and then strand me in the worst situation. Today I touched up all the solder joints on the card as instructed and it worked the first time. I will give the old girl some more opportunities to strand me where there is no time constraint and let you know. Thanks for the great information!