Does anyone understand the MB entry/alarm systems?

[Merc Owner 2B]

I realise that over the years there must be different protocols for locking/unlocking cars with their remotes.

A few years ago, whilst in France, someone opened my ML250 (W166) whilst I was in a service station. They stole our mobiles from the centre glove box and relocked the car. When I came back to the UK the dealer was able to tell me (via STAR) that there are only two keys registered to this car and both had been used. So how could someone else have opened it I asked? They couldn't they said and probably believe I left it unlocked, which I KNOW I DIDN'T!

I asked about the old-fashioned way of capturing signals using a laptop etc when someone locks a car and then retransmitting that signal when the person is out of sight. They said it was impossible as every time you lock the car it sends details to the remote of the next signal it needs to unlock (rolling codes).

I've since heard of a few similar issues to newish MBs so today tried a theory. I used my spare key (hasn't been used for about a year). It opened the car on the first press and started it on the first turn. So the rolling code explanation doesn't seem right.

Does anyone have a reasonable explanation of how the system works? I guess the crooks already know so we wouldn't be helping them!

I know of someone who has had his car broke into three times now on his own driveway. If someone were to "capture" your code/frequency will it always be able to open your car?

 

[whitenemesis]

The rolling code is key specific, so even though that key hadn't been used for a year the car still knew what code to expect from that key.

 

[Sp!ke]

Normally what happens is that they user a jammer to block your remote so it doesn't lock the car when you use the remote. (you just thought you locked it)

You can lock the doors without the key if the front doors are shut.

 

[rf065]

You know Mercedes don't make alarms, so my insurance documents state the car is alarmed & immobilised with a Clifford Concept 500, factory fitted. Not sure if Clifford would supply any info or not?

Russ

 

[markmifsud]

The Key control system is MB specific and not directly part of the alarm

 

[Merc Owner 2B]

Normally what happens is that they user a jammer to block your remote so it doesn't lock the car when you use the remote. (you just thought you locked it)

You can lock the doors without the key if the front doors are shut.

In my case I saw the mirrors fold and indicators flash so know I locked it so am still wondering how they opened it.

 

[Sp!ke]

All I can think of then is perhaps you accidentally unlocked it when walking away.

As the dealer said, the only key to unlock your car was yours.

 

[Giantvanman]

Might you have accidentally pushed a button whilst the key was in your pocket?

 

[Merc Owner 2B]

Might you have accidentally pushed a button whilst the key was in your pocket?

You never know for sure.

The other car I know of has been opened three times on it's own driveway.

There has to be a way of opening them.

 

[markmifsud]

You never know for sure.

The other car I know of has been opened three times on it's own driveway.

There has to be a way of opening them.

Not sure there is, nearly all stolen mercs have been via stolen keys/spare keys not removed from the EIS or lifted on the back of a low loader

 

[WG M-B]

Not sure there is, nearly all stolen mercs have been via stolen keys/spare keys not removed from the EIS or lifted on the back of a low loader

This is why we remove keys from the eis when a customer buys a vehicle without all the keys! Thieves love this method!!!!!!!!

 

[Dec]

There is a difference between opening a car door and starting the car engine.
A car door lock can be picked, as long as the car has a reliable faulty alarm then picking the lock will get you inside the car.
To start the engine, you need the key or a clone of the key.

Dec

 

[markmifsud]

There is a difference between opening a car door and starting the car engine.
A car door lock can be picked, as long as the car has a reliable faulty alarm then picking the lock will get you inside the car.
To start the engine, you need the key or a clone of the key.

Dec

If the door had been mechanically unlocked then it would have been stored in the PSE as an alarm activation, even if the actual siren was faulty.

 

[Dec]

My point was that if the car has a faulty alarm, which is quite common, then there is no alert and so the intrusion into the car is seen as a mystery , and presumably no one put the car on star after the brake ins.

Dec

 

[markmifsud]

Quote OP
They stole our mobiles from the centre glove box and relocked the car. When I came back to the UK the dealer was able to tell me (via STAR) that there are only two keys registered to this car and both had been used
Un Quote

He did have it checked for method of entry. We can only assume that they did check for alarm activation's whilst they were checking which registered keys had been logged by the EIS

 

[Dec]

I should have quoted post #9 because that’s the post that I was responding to.

Dec

 

[Benzowner]

How would someone get into a car, if say, the keys were locked in the boot? I would assume the AA/RAC/Whoever would know how to gain entry