E Class alarm problem - please help.

[dmu]

Hi

I am struggling with my mates E Class alarm. The car has been stood in the garage since well before Christmas and now when he tries to lock it with the remote it flashes twice to answer back and locks all the doors as it should but then it immediately starts flashing the indicators very fast until the alarm sounds.

Is there a way of re sync'ing the alarm or could something else be wrong?

Thanks in advance.

 

[television]

I would disconnect the battery for 10 mins and then try again

 

[dmu]

Will do - thanks.

Is there a procedure for re-sync'ing the remore?

 

[television]

Press any button and insert into ignition and turn to 2 within 30 sec

 

[bigasotonuk]

Hi,
What year is the car? and what type of key do you have?

 

[jberks]

if its responding then it isn't a resync.
The fast flashing is normally an indication that the alarm can't set due to a problem. Say a door not closed properly or some other sensor issue.

 

[Dosco]

Water ingress in the alarm unit caused mine to fail in a similar fashion. New alarm unit cured the problem.

 

[television]

Water ingress in the alarm unit caused mine to fail in a similar fashion. New alarm unit cured the problem.

Yes we must have had 10 cases of faulty alarm horns this last 6 weeks

 

[bigasotonuk]

Hi

I am struggling with my mates E Class alarm. The car has been stood in the garage since well before Christmas and now when he tries to lock it with the remote it flashes twice to answer back and locks all the doors as it should but then it immediately starts flashing the indicators very fast until the alarm sounds.

Is there a way of re sync'ing the alarm or could something else be wrong?

Thanks in advance.

You say its been stood before Christmas, you have re-charged the Battery? As you don,t say so.

 

[television]

And that 211 could have 2 batteries, are they both charged

 

[dmu]

Thanks for replies all.

It has had new fob batteries.

When you say re-charged the battery, you mean the main starting battery? Yes he has been charging it on and off as he says it won't start after a long period of time. There must also be a reserve battery as when I was doing all the checks that I could find info on the alarm sounded with the main battery disconnected. I read somewhere there is a back-up in the boot for the alarm.

I disconnected the bonnet switch and short circuited it and worked all the door and boot light switches which all seemed to work.

He left the battery disconnected overnight (just in case there was a capacitor or similar holding charge) but still no different.

Will charging the battery cause a problem?

Cheers.

 

[television]

I am sure that on a pre 2005 211 there are 2 batteries, one under the rear seat or in the boot.

 

[bigasotonuk]

Most MB's have battery back-up for the alarm siren, and as Malcolm says the early 211 chassis had 2 batteries.
We still need to know what year the vehicle is, and a description of the key/key fob.

 

[dmu]

OK will get some more info.

 

[dmu]

It is a Feb 2001 E220CDi. The chassis No starts WDB 210 and the key has three buttons. You place it into a socket and it then gets sucked into the dash so you can start the car.

Does this tell you what you need to know?

Thanks and regards

 

[bigasotonuk]

If the car battery is fully charged, you could try checking all the door & boot (you may have one fitted to the bonnet as well) pin switches are clean and operating ok, failling that put some masking tape over the internal movement sensors mounted at the top of the "B" pillar.
A very common fault with these alarms is the back-up battery in the siren, though you did say the siren worked with the car battery disconnected, so I think we,ll have to eliminate this.
There maybe other things too try regarding this alarm that others may offer up, but if you were to plug into "STAR" (MB Diagnostic computer) it should give you a better idea of the problem.

 

[dmu]

Ok thanks

I have got somebody coming tomorrow who reckons his kit will read it.

I will try taping the sensors and report back tomorrow.

Cheers.

 

[television]

The 210 only has one battery

 

[dmu]

Hi folkes

We have now had this car on a diagnostic tester and it has vcome up with "alarm back up battery low voltage".

Can anyone show me a photo of this battery of give me an accurate description of where it is please?

Also - any ideas of part Nos and price and where to get one from?

Regards

 

[bigasotonuk]

As I posted earlier in the thread this battery is actually in the alarm siren, which is fitted in the passenger side wheel arch (front).
The battery cannot be replaced on its own and a new siren has to be sourced, this is a very common problem with this sort of alarm system on vehicles of this age.
There are several different types but let MB order it from the chassis number to ensure correct fitment, the one fort my C class was approx £50, less than a year ago.