Immobiliser - I think!

[CAT220]

Over the past couple of weeks ive been experiencing intermittent starting problems. I have a 1994 E220, ive had the car for 6 months now and had no probs until recently.

I open the door using the key as the car doesnt have remote locking, when I turn the key in the ignition the car "tries" to start but doesnt, have found that if i get back out lock the car, open the car, get back in (a couple of times) it eventually starts. Feel like a right dumpling doing that though!

Does anyone know what the connection is between the central locking - ignition and immobiliser?

Any help would be appreciated.
Cheers,
C

 

[Brian WH]

Does anyone know what the connection is between the central locking - ignition and immobiliser?

Any help would be appreciated.
Cheers,
C

I thought the immobiliser on the early E classes were purely off the ignition switch. So getting in and out is not doing anything?

Try just putting the key in and out and starting to see if it has the same effect. I would bet that it is the ignition switch playing up.

 

[CAT220]

Thanks for the response Brian. Can ignition problems be costly? Suspect i know the answer to that!

 

[Brian WH]

Thanks for the response Brian. Can ignition problems be costly? Suspect i know the answer to that!

Not cheap but worth asking at the dealer first before spending money.

 

[grober]

Has the car an alarm or just an imobiliser??

 

[CAT220]

Has the car an alarm or just an imobiliser??

The car has an alarm but I dont use it When i bought the car the previous owner said he had "switched it off" and being honest ive not even bothered to look at turning it back on.

 

[grober]

In my e220 the alarm is tied to the immobiliser. Basically the alarm activates 2 relays/switches in a separate unit which interupts a couple of ignition and fuel pump relays from operating. This allows the starter to turn over but no ignition no fuel the car wont start. From your symptoms maybe these immobiliser relays/switches are faulty and only working intermittantly. PROBLEM with cars of this vintage is that all the alarm systems are ONE/OFF after market dealer fitments so no 2 are exactly the same. Your problem could also be be with one of the true MB relays (nothing to do with alarm system). Intermittant problems with either fuel pump relay or overvoltage relay can also give symptoms like this. If you want check these out they are beside the engine ecu and abs units covered by a black plastic cover behind the battery. Replacement is the only effective long term solution !! You really need to be comfortable with vehicle electrics to get into this territory so get help if you feel out of your depth. Also contact the previous owner to see how he "switched off" the alarm

 

[Rory]

Over the past couple of weeks ive been experiencing intermittent starting problems. I have a 1994 E220, ive had the car for 6 months now and had no probs until recently.

I open the door using the key as the car doesnt have remote locking, when I turn the key in the ignition the car "tries" to start but doesnt, have found that if i get back out lock the car, open the car, get back in (a couple of times) it eventually starts. Feel like a right dumpling doing that though!

Does anyone know what the connection is between the central locking - ignition and immobiliser?

Any help would be appreciated.
Cheers,
C

Funnily enough a couple of months ago I had a brand new C270 demonstrator that did this (once in the 3 days I had it). I was completely baffled and it was only by thinking ‘I must be doing something stupid, I’ll get out and start all over again’ that it started – straight off this time.

 

[jonno]

Immob

I have a 95 e200 estate (w124)> It has an alarm/cl/immob. When you unlock the car you have about 15/20 seconds to put the key in the ignition before the immob kicks in. If you try to start it turns over but won't fire up.
Could it be that you are not putting the key in the ignition quick enough?
Incidentally it drives me banana's and have still not found out how to switch off the immobiliser.

 

[del320]

I have a 95 e200 estate (w124)> It has an alarm/cl/immob. When you unlock the car you have about 15/20 seconds to put the key in the ignition before the immob kicks in. If you try to start it turns over but won't fire up.
Could it be that you are not putting the key in the ignition quick enough?
Incidentally it drives me banana's and have still not found out how to switch off the immobiliser.

Don't go there, mate.
Is a keen wind not blowing tumbleweed across your screen? You're entering a parallel universe where such matters must remain beyond your ken!
ssshhhhhh

Maybe it just affect us boys from Scotchland

 

[sedstevo]

Over the past couple of weeks ive been experiencing intermittent starting problems. I have a 1994 E220, ive had the car for 6 months now and had no probs until recently.

I'm having similar problems myself and would be interested to know if you have you resolved your problem?

Regards

 

[grober]

See another thread for solution

THIS PROBLEM WAS SOLVED SEE THIS THREAD! http://www.mbclub.co.uk/forums/showthread.php?t=16643&highlight=W124+START I dont know if this solution would apply to your model of MB

 

[jonno]

immob

I have discovered that the immob prob occurs when a door isn't closed properly ie at a petrol station (or when the wife is waiting to get onto a ferry). The circuit is obviously broken and the alarm (which is turned off) goes off and the immob kicks in. You then have to re-set it. Open close boot and insert key into lock. turn clockwise(lock) and then anti clock to unlock. Go to drivers door and lock then unlock with remote. Light should flash green. If not keep trying and eventually it works.
However if anyone knows how to disable the immob I would love to hear from them!!

 

[jgevers]

Hi,

Most W124s had a Scorpion alarm/immobiliser fitted rather than the integrated system of the later MBs. The immobiliser circuit can be problematic. The best idea is to get your local auto electrician to remove the immo. circuit.

But you have to make sure that the overvoltage protection relay has no dry joints in it and the output voltages are correct.

regards,

Job

 

[del320]

Immobiliser 124 series.

I posted this last week purely for info only.

I don't know if this vexatious problem only affects Scottish Mercs but having wasted a great deal of my precious time on two occasions over the past nine months (and only 3k miles) I can tell you all the ECU upgrades, engine transplants and airboxes are not worth a hill of beans when the immobiliser throws a wobbly!

So - here's my definitive view on those immobilisers fitted around '95 - '97 to 124 series cars and possibly 202 and early 210s.

They were dealer-fitted, feature a fold-out key and a red/green LED is fitted in the driver's door and below the bootlid. It re-arms in around 45 secs if you don't start the car.

Being aware of the shortcomings, I habitually carry a spare working key and a further set of batteries secreted about the car and wifey carries a broken key at all times which will at least let me into the car.

The small key only turns off the alarm siren. Battery failure and susequent resetting of the alarm has been covered exhaustively elsewhere on the Forum and is detailed in your manual.

In France, last year, the failure was down to the door LED having blown. Part A1248200297 - £120.13 ex vat and fitting. Total bill £400. It's failure broke a circuit - a bit like a house ring main, or your xmas lights!

Last months' failure was a blown relay - the one Graeme correctly refers to in his very helpful post. Because of this, any knowledge of how to bypass the immobiliser would have been of no use in restarting the car as the relay controls the ignition and fuel pump. Only an expert sparks would be able to identify and repair a blown circuit within it.

The French experience, and key/battery failure, however, are both a simple bypass job and I have now been shown what's involved. While not in the least difficult, it is not a procedure easliy explained here. Far better to go to you friendly dealer and ask to be shown (whilst gripping him gently by the throat )

All credit to Western Edinburgh for their free and helpful assistance!

 

[Chumneywarner]

Hi,
I'm having no end of problems with my E300D, W210, 1996. It seems to be the immobiliser. Doors lock/unlock OK with remote, but car turns over without starting. During ignition on, red & green LEDs flash alternately (please see my thread 'Immobiliser - Engine non start for details).
Please could you PM me where the OVP relay is & what wires need bridging on the alarm/immobiliser, as from what I am reading on the various MB forums, these immobiliser & key problems are very common.
Thanks
Garry