S320 '97/reg immobilizer locked up

[bikerdave]

Hi every one,

I'm David. I have bought a 97 s320.
i collected it from the garage knowing that it didnt work to build a nice new car out of as a project. the garage had inspected the various places that are mentioned around the immobilizer under carpets etc. they had ripped the wring block form the pump under the rear seat.

i have put it back now.
could any one tell me please how to disable the immobilizer. (i dont know if the alarm works and the ctrl locks are dead)

 

[Dec]

What kind of key do you have and is it working properly?

Dec

 

[bikerdave]

i have the one that's marked flip out 1994, its got new batteries, it doesn't have the contact shown in the photo.
although when you hold the button it flashes to show its got power.
it does make the lights go on the r v mirror when you press the button and indicators flash.
after the "two beeps and put key into ignition, turn to pos 2" the red and green on the mirror flash alternatively red and green.
on key pos 1 the srs light is on.
a whistling is coming from what i think is a relay, on the passenger side of the engine bay.
Thanx for reading. Dave

 

[Dec]

Some of those keys had an immobiliser chip inside the key case, located (glued) just below the Red lens as in picture below.

This immobiliser chip is energised by a transponder coil surrounding the ignition switch so when the key is put into the ignition the immobiliser is disabled so the car can be started.
Here is an example of a transponder coil, about ¾ way down this page here… Bert Rowe's-A-class info. Hazard warning, car keys, re-synchronizing remote keys, Central locking.
Sometimes this chip can become loose inside the key or lost if someone opens the key case, just one possibility explanation for the problem.

If your ignition doesn’t have a coil then you don’t have this chip and your ignition surround will look like the one pictured below.

Your key, when pressed and viewed through a digital camera should look like the video below.

[YOUTUBE]zQhwvjw29NA[/YOUTUBE]

Dec

 

[bikerdave]

Hi, the key does look that the video. There is a wire coming from the ignition barrel cover going to a box seperate from the ignition circuit.

The key doesnt have a transponder chip but looks as though there was something there once.

 

[Dec]

Any chance you could put up some pictures of the key internals, if you have the coil around the ignition then you should have a chip inside the key.

As the key turns in the ignition then it must be the correct key….. unless someone in the past changed the ignition lock barrel AND the key blade as well, see does the key blade work in the door and boot lock, its quite likely that these locks are seised due to non use, squirt some WD40/penetrating oil inside the door and boot key holes, if the lock barrels seem seized.

What type of alarm siren is on the car and any alarm stickers on the rear side windows, pictures would be useful.

Dec

 

[bikerdave]

Hi Dec,
I do think its possible that someone has installed an overrider at some point, but mr Ali next door who owned it last said everything electrical was fine until the battery was changed.

 

[bikerdave]

i dont know if that siren is even connected to the original loom

 

[Dec]

Unplug the siren and see what happens.

Dec

 

[Dec]

Thanks for the pictures, very useful.

Is there no chip in the other halve of the key case?...not pictured.

That small 3 prong key is to bypass the immobiliser , there must be a socket somewhere in the cabin or inside the glove box that will take that key.

Dec

 

[r129 300sl]

The immobiliser key looks like a scorpion system, as fitted to the original A class.

 

[Dec]

The immobiliser key looks like a scorpion system, as fitted to the original A class.

Looks similar alright, this should be useful, here... Bert Rowe's-A-class info. Information A160/Feb 2002 Scorpion Car Alarm System.

Dec

 

[bikerdave]

Pulled siren, nothing. Alarm flashing, wont reset.

Car now in process of being stripped, looks like ill have to design my own loom.
Thanx for the advice though guys. David

 

[bikerdave]

does any one have a schematic for the 1997 s320 please

 

[Dec]

http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1997/S320/SYSTEM WIRING DIAGRAMS/
Above may not be very reliable, for instance the “alarm horn” is shown as having 2 wires, I think yours has 3 wires.
http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1997/S320/SYSTEM WIRING DIAGRAMS/6303.pdf

The act of unlocking the car with the remote (even if the doors aren’t unlocking) should also disable the alarm.

Dec

 

[bikerdave]

Thanx, i found those diagrams on autolib last night.

i am going to go down to just a starting circuit and then begin adding the ecm circuits one by one, til i get engine/ign failure. theoretically i will the fault.

i also found out that the 1997 s320 has had 3 recalls for defective and below minimum uk specs for the insulation on the entire loom. Alledgedly Mercedes admit that even just time can destroy these looms, yet they have repeatedly refused to do anything for anyone. Thanx, David

 

[bikerdave]

Got the diagrams, yes alarm has three wires, the diagrams are quite correct if you factor in that Germany has some very strange practices when it comes the anti-theft circuitry on its vehicles. (un-fortunatley the only nation left that knows wiring as well as uk is japan.)

Alarm circuitry was murdered horrifically last night,

 

[Dec]

I bet it wasn’t screaming when it died, if you do an autopsy on the siren you will find something like this here… Alarm / Siren Issues : Goes off for no reason/Kills Battery FIX DIY.. - MBWorld.org Forums

It might be worth while and fruitful to get a competent indie to put the car on STAR diagnostic to see what fault codes might be revealed.


Dec