W124 alarm problem

[paulc86]

Good evening all, just in the process of buying a W124 220TE, the car has sat for a couple of years now with the battery removed. I fitted a new battery and replaced the battery in the keyfob but it still won't turn over.

I get all ignition lights etc but the alarm keeps going off and it is almost as if the car is still immobilised.

I have had a look at the various guides etc about reprogramming the fob but none seem to apply to this model. It is a 1993 prefacelift with the M111 16v engine.

Here is a pic of the fob, it looks genuine mercedes but unlike the ones i have seen in the guides:

Any help would be greatly appreciated as i am at my wits end!

Thanks in advance, Paul

 

[trapperjohn]

I had a pre face left 220 TE with exactly the same alarm fob! and I guess therefore, alarm system.
They are a danged pain in the butt. The alarm self sets after 30 seconds of exiting the car (well mine did) so if you get out to put some petrol in or do some work on the car or something you have to set the alarm and reset before you get back in or it goes off.
How did I get round it. Sold the car (after two happy years) I always intended to get the alarm taken off but never got round to it.
Not much help so far eh!! In the glove box you should have a key switch which you can turn the alarm off with. That is as long as you have the alarm key on the bunch. It looks like a small key you would open a one armed bandit with or one of the older parking meters. Failing that get a sparky to it.
Maybe one of the techies can help.

 

[paulc86]

This key:

 

[trapperjohn]

Yep thats the puppy.

 

[Dec]

That is as trapperjohn says a key the turn off the alarm. If the car battery is dead or disconnected, when it is reconnected the alarm will automatically re arm itself, this takes it about 20 to 30 seconds.

Pressing the left button should disarm the alarm, it may be that the key fob is defective or its 12v battery is not installed correctly. The Red led on the key fob should light up when the button is pressed.

Look under the steering wheel, above driver’s legs/knees for the key hole for that key, also look on the back of the siren, there may be a key hole hidden under a weather/dust bung.

Dec

 

[paulc86]

I will give this a go. Thanks you very much!

So is the car likely to be immobilised or is this just an alarm? Will using that key turn of said immobiliser if there?

 

[paulc86]

When either button is pressed on the fob the red LED lights up. Is there a way that this remote could possibly need recoded to the car?

 

[trapperjohn]

Sorry out of my depth now on your post 7. Have you tried standing as close as possible to the receptors for the alarm when you press the fob? It could be a very weak battery in the fob. Receptors are in the drivers door and boot door as far as I remember.
Post 6. As far as I can guess both the alarm and Immobiliser will be switched off with the key.
Suck it and see job I'm afraid Paul.

 

[scillyisles1]

The alarm is a Scorpion alarm that was marketted and fitted by MB dealers as an official MB alarm. The left key fob button toggles the alarm on an off whilst the right fob button sets off a panic alarm.
The siren is typically mounted under the bonnet and the key you have fits into the back of the alarm siren unit to disengage the alarm.
The alarm electronics are held in a control unit about the size of a large cigarette box which is normally found underneath the drivers dashboard. The alarm control box has an aerial wire coming out of it to pickup the rf from the remote.
The alarm system uses a rolling code and needs to be resynced to the control unit. AIRC resynching involves holding the left fob button down for 30 seconds or so. The battery in the remote needs to be good (GP10 battery AIRC)

 

[Dec]

There were different versions of the alarm and different ways the were wired up, some of these alarms immobilised the car some did not or the were integrated with the existing Mercedes immobiliser.

I have a similar Scorpion alarm but in my case I have a flip out key fob which handles the factory fitted immobiliser, the Scorpion fob arms and disarms the alarm and has nothing to do with the immobeliser.

Is it just a flat metal key that you have, have you tried locking/unlocking the door with it and does the starter motor turn like the car is trying to start?
Was anyone turning that screw on the fob in first picture? Don’t know what it does but it could be some kind of adjuster, for factory use only. The key fob can only be programmed by Scorpion.

John, what kind of keys were with your car?

Dec

 

[trapperjohn]

Mine was a standard key not one of the flip out jobbies.

 

[Dec]

Found this..

Resynchonisesation of the remote.
In the event the system fails to switch off, by depressing the on/off button undertake the following steps.

Hold down the on/off button for approx 10 seconds while standing within the normal operating range.
Where the system will still not switch off replace the battery in remote and repeat above step. (12v alkaline GP 23 or equivalent)

If the vehicle battery has been allowed to become depleted it is necessary after recharging the battery to adhere to the following set up sequence.

1…turn ignition on
2…reconnect battery
3…turn ignition off
4…press remote control for 10 seconds

Dec

 

[paulc86]

It is just a flat metal key same as the earlier ones, i will give the ideas in this thread a go. Cheers for the help guys.

 

[tintinmt]

I had a similar system in my 320CE. I have removed it now and replaced it with a current compatible system from Scorpion. If I understand it correctly, the only element of the system that 'imobilises' the vehicle is the part that disconnects the power to the starter motor. The rest of the system just operates the locks and the alarm sounder (apart from the bits that detect unauthorised entry). If your round key fits into the alarm control unit (probably under the dash as described by previous posters) then you should be able to eliminate the alarm from your enquiries by turning it off. I also seem to remember that the operating and installation instructions for these systems were available online somewhere. You will need to identify your model number.

 

[kth286]

try locking and unlocking the car a few times from the drivers door lock.

there is probably a relay sticking from being unused for those years.

 

[paulc86]

I have been having another go at it today. The small key doesn't turn the alarm off at all so i am pressuming there is some kind of fault with the system. Over to the pro's me thinks. Cheers for all the help.

 

[Dec]

Will the key do a quarter turn in the key hole…can’t remember if it is to the left or to the right… it should turn off the alarm, have you any flashing indicators when the siren is sounding?

Where is the keyhole located, inside car or on the siren?


Dec

 

[paulc86]

The wee key hole is in the glovebox, It turns a 1/4 turn. The indicators are flashing and the siren is sounding, i disconnected the siren as it was piercingly loud and the car is in a very quiet part or Troon!

 

[Dec]

That switch should be turning the alarm off, turn the ignition on and try the wee key again.

Will the central locking switch work on the dash and do you hear the vacuum pump run?
Also have a look at the vacuum pump for anything suspect, this is a saloon, don’t know if it is in the same place on an estate… PeachPartsWiki: Keyless Entry Install


Dec

 

[paulc86]

Tried it with the ignition on and off, still didn't work. Central locking all works spot as it should. Just can't get the alarm to disarm.