W220 Ignition Key will not turn???

[Bladerunner2125]

Well the problems continue with this 2002 W220 S320 , on Sunday the Ignition Key stopped working, it flashes when I press the buttons but will not turn in the ignition nor does it operate the central locking, its like the car does not see the key? Have checked the main car battery and that is outputting 12.7v at rest, I only have the one key with this car, I rang a locksmith and he said it is more than likely the EIS whatever that is? what do you guys think?

 

[Dec]

The coil could? be broke on the PCB.
Was the key dropped or subject to a shock recently?
EIS is the Electronic Ignition Switch.
See ... MERCEDES 3 BUTTON KEY FOB REMOTE INDUCTANCE COIL E C CLASS E CLASS | eBay

Remove the PCB.

https://www.youtube.com/watch?v=cINrKin06ts

[YOUTUBE]cINrKin06ts[/YOUTUBE]

Dec

 

[Bladerunner2125]

The coil could? be broke on the PCB.
Was the key dropped or subject to a shock recently?
EIS is the Electronic Ignition Switch.
See ... MERCEDES 3 BUTTON KEY FOB REMOTE INDUCTANCE COIL E C CLASS E CLASS | eBay

Remove the PCB.

https://www.youtube.com/watch?v=cINrKin06ts

[YOUTUBE]cINrKin06ts[/YOUTUBE]

Dec

Dec thanks for the link, the remote has not been dropped at all, I had not used it since Friday then on Sunday came to use it and it would not do anything, I purchased this car from a decent trader so I still have warranty, I paid a bit more than the book price but in hindsight I am glad I did, they are picking the car up in the morning bringing a car trailer.

 

[Dec]

Nice to have the back up of a warranty in place, let us know what caused of the fault.

Dec

 

[Bladerunner2125]

Dec, Yes its a limited warranty 2 months, will report back to the forum with whatever they find? if its just the remote then it should be an easy fix fingers crossed!

 

[markjay]

My understanding is that if the EIS need replacing, a new EIS unit will need to be ordered directly from Mercedes Benz, i.e. it is not possible to purchase a second hand unit and re-code with STAR etc. The prices I saw mentioned online were in the region of £500-£1,000.

There are quite a few firms out there who claim they can repair faulty EIS units, though I have not seen any particular one who came recommended by forum members.

However as suggested it could be a simple mechanical problem that can be repaired DIY.

 

[Bladerunner2125]

What actually breaks in the inductance Coil in the Keyfob, is the centre of the coil made from ceramic? or is it just the contacts that break?

MarkJay, just how common is the problem with the EIS, £500 to £1000 for a replacement unit is an awful lot of money, you would think manufacturers would recognise that some none moving or mechanical components in their original design that are not subject to normal wear and tear are just not manufactured to an high enough standard to survive the life of the vehicle and should in my opinion be made available at minimum cost and 0% profit to the buying public, £1k for a badly designed component could for many mean the vehicle has to be sold!

 

[markjay]

What actually breaks in the inductance Coil in the Keyfob, is the centre of the coil made from ceramic? or is it just the contacts that break?

MarkJay, just how common is the problem with the EIS, £500 to £1000 for a replacement unit is an awful lot of money, you would think manufacturers would recognise that some none moving or mechanical components in their original design that are not subject to normal wear and tear are just not manufactured to an high enough standard to survive the life of the vehicle and should in my opinion be made available at minimum cost and 0% profit to the buying public, £1k for a badly designed component could for many mean the vehicle has to be sold!

I am not sure how common it is, the information I have is from researching it when I thought my EIS was causing issues, though now I don't think it's the EIS in my case so did not take it any further.

My understanding is that the high cost is due to it being a special-order dealer-only part (though it can be ordered and fitted by an independent - it comes from MB preconfigure for the car and it's a simple plug-and-play installation i.e. it does not require STAR for fitting).

 

[Dec]

Being a coil, the centre should be iron, if it is broken then it needs to be replaced, as in my eBay link above. Sometimes the coil can be reattached by soldering to the PCB if the wire connection is broken, I think the remote fob fault is more common than a faulty EIS… a completely flat car battery could also stop the key being accepted.

Dec

 

[Bladerunner2125]

Dec, a completely flat battery would allow the Keyfob to lose sync with the car? thats really worrying as well, do you know why that would be? is it the EIS that holds the ID info for the Keyfob? you would think on such an originally very expensive vehicle the car could hold the ID of the Keyfob even when a battery is discharched, could changing the car battery also cause loss of sync? is there a way of reprogramming the Keyfob after its lost sync?

 

[Dec]

The key fob doesn’t lose synch unless its without its two 3v batteries for more than a minute, once the key is put into the ignition, then its re-synched… as long as there is some power in the car battery.

There is a magnetic field around the ignition switch, this magnetic field energises the coil inside the remote fob (if the coil is not broken) this tells the ignition it has the correct key and so the car starts.

I’m saying if the car battery was completely flat then there wouldn’t be any power in the ignition so the key wouldn’t be recognised, is the car battery completely flat? if the hazard lights don’t work then the car battery is completely flat.

Also, the 2 batteries inside the remote fob have nothing to do with starting the car, the just power the fob to operate the central locking, open and close windows and arm/disarm the alarm when locking the car.

Dec

 

[Bladerunner2125]

The battery is pushing out 12.7 volts tested it with a Multi-meter, the Keyfob is emitting an infrared signal tested that with the camera on the phone, I left the Keyfob in the ignition for a couple of hours yesterday that didn't help either, maybe it is the EIS that is faulty?

This whole thing about flat batteries causing Keyfobs to lose sync is really worrying though everyone gets a flat battery at some point in a cars ownership, is this a vehicle age related problem or could this have happened to a brand new W220 back in 2002?

 

[whitenemesis]

A flat car battery will not cause the fob to 'loose' sync. If it did one would have to re-sync each time the battery was disconnected for whatever reason..

If the fob's internal batteries are left out long enough then, yes, synchronisation will be lost but re-sync'd as soon as the fob is placed in the ignition.

Infrared output from the fob has nothing to do with being recognised, turning in the lock or starting the car, as Dec explained, that is done via induction once the fob is inserted in the ignition switch.

 

[Dec]

A flat car battery doesn’t cause the key fob to lose synch.
If the 2 batteries inside the remote fob are removed for more than a minute then the key may lose synch, however, putting the key into the ignition will re-synch the key.

Dec

 

[Bladerunner2125]

So it must be either the Coil is broken in the Fob but I don't see how that could have happened? or the EIS is playing up? what else could it be stopping the Key from being detected by the cars ignition system?

 

[Dec]

It is most likely either the coil or the EIS, you could open the remote to have a look but that would be unwise as the car is under warranty, so best not to fiddle with it, let the trader sort it out.

There could be some other fault but that's unlikely.

Dec

 

[whitenemesis]

Broken coil is far more common than EIS failure. One only has to drop the fob for the coil to become detached. Easy enough to open it up and check.

 

[Bladerunner2125]

(Update) the independent garage doing the diagnosis sent the data to someone else to interpret, they are saying key or Ignition? maybe they would be better just speaking to you guys been a lot quicker in their diagnosis! trader wants to obviously try the cheaper Key option first, then its the £500 ignition module if that does not work?

Just wondering if these Keys can fail without being dropped, since I know for certain it wasn't dropped?

 

[Dec]

A new key will be a welcome resolution, hope that’s all it is.

If you are wealthy, you should get a spare key made, very useful in the case of loss or indeed a fault, if it is indeed the key.

Key C, below, is more likely to suffer a broken coil than key B, don’t know if the can become faulty by any other means other than an impact or just a simple broken solder joint without any impact.

Given the age of the car, it would be wise to test the alarm system, the alarm siren can cause problems when it is about 10 years old.

To test, trigger the alarm and let the test run for 3 minutes, the alarm should reset after 3 minutes, the link below describes how to do it.
http://www.mbclub.co.uk/forums/electronics/169666-w202-how-test-car-alarm.html

Dec

 

[Bladerunner2125]

Dec, the key that I have is the one on the right (C) will see what they say tomorrow when they try the new key? will also get them to test the alarm system as you mentioned, I always intended to get a spare key, one is just too risky, will see if the trader can get me one at trade price, might also be worth getting the old one back if its faulty and trying to repair the Coil if it is a faulty key?