Help my key no longer works and cars gone mad

[Adantiques]

I'd appreciate a bit of help if poss before having to go to the bandits at Mercedes .Basicly I've got an 06 merc sl 350 which up until now has been pretty reliable other than the standard boot leak which got sorted when I first got it.
My wife tried to use the car today but it wouldn't unlock.I automatically assumed new fob batteries required so I replaced them and tried my self.Nothing happened!I then opened the door with the blade and the alarm went off.I started the car and pushed the fob buttons but nothing happened.I then turned the key off in the ignition and took it out but the engine carried on running with the alarm going mad.I then gave up and called the AA.When he turned up he was convinced it was the ignition part that the key goes into as the key wont now turn in the ignition although it will if you disconnect the batteries then connect them again.
Anyway the AA man left me with a car that's had to have the battery disconnected and the drivers windows are now halfway down and won't move.if I reconnect the battery in the boot the car will start but not turn offhand the alarm goes mad.I don't have a spare key.Any ideas would be much appreciated .

 

[television]

Oh dear it does look to be an EIS switch fault, key maybe, but I do not think so

In the morning when you join up again if the key has come out, put the key in and press any button twice on the key with 3 seconds just to see if it will re sync

 

[Adantiques]

Thanks for the info but I've tried doing that today with no effect.The AA guy seemed to think it was a fault with the Eis but really just ended up pulling the dashboard apart and leaving the car with the windows open.
I can't work out how the alarm can go off but the car can start without the immobiliser kicking in.I think I'm going to have to give up and let Mercedes have it,trouble is the one near me in Loughton aren't upto much.When I'd had the car about a year or so the central locking pump went due to water ingress.They repaired the fault but didn't solve the problem.I ended reading your articles on the cause and getting my mechanic to replace the rear screen seal.

 

[bigtwin]

I can't work out how the alarm can go off but the car can start without the immobiliser kicking in.

I've never figured that out either, but my wife's old A Class would happily do the same. The new one - W169 - does a neat trick of pretending to lock the doors, but you can actually open the OSR. The alarm goes off, then you can start it and drive along with the alarm going off.

Methinks Merc security isn't all that one might hope for....

 

[roscoc180]

Had similar problems when I had water in the passenger footwell, all your problems apart from the alarm but mine was left unlocked at the time of problem.

 

[Adantiques]

What was the cure with regards water in the footwell.It could well be that causing the problem as the car has been misting up quite a lot recently.

 

[television]

If the front heater box drain gets blocked with leaves, then water can get in on the passenger side and go down to the sill that contains the CAN B and wake up cables, this can confuse the whole network and the car does silly things that do not make sense.

It is near impossible to lift the carpet much without removing the passenger seat to get to the lower sill boxes that contain the wires

 

[Adantiques]

That may be the problem as I had one of those remote roof controls fitted about a year ago.that was on the passenger side and my mechanic said it was very wet there.He dried the area out and assumed it was a leak from before I bought it and repaired the rear window seal.After reading some of the posts I now realise the cause of the water is what you said and chances are waters got in again.If I pull the carpet up and dry this cab b thing out will that solve the problem.

 

[SL63 Mark]

You can check if its wet under there by lifting the carpet and having a feel. If its wet, that needs sorting.

 

[television]

That may be the problem as I had one of those remote roof controls fitted about a year ago.that was on the passenger side and my mechanic said it was very wet there.He dried the area out and assumed it was a leak from before I bought it and repaired the rear window seal.After reading some of the posts I now realise the cause of the water is what you said and chances are waters got in again.If I pull the carpet up and dry this cab b thing out will that solve the problem.

The seat does have to come out as the cables are in trunking with large flat top lids.

The seat comes out easily, just 5 10mm bolts, and then tip the seat back and remove the electrical connector and vacuum line if fitted.

When the seat is out, remove the cap from the large screw head in the side kick panel, Take out the screw then pull the draught excluder away and the side panel lifts out.
You can now roll back the carpet and unclip the big black lids from the cable boxes.

The first connectors are the wake up and are blue in colour, the next row are the CAN B X connector. Any damp or water around these connector will and do upset the whole car. The EIS is the master controller for the CAN and wake up.

These connections if wet give false and meaningless messages that are usually non plausible. The big problem is that only digital bits are sent on CAN lines, they carry no current and cannot self heal when poor or have contaminated connections.

 

[dermot dublin]

Similar problem on c180 1998

Hi sounds similar to the problem I,m having - see my post re "ignition key wont turn"
Both passenger side foot wells are soaking and car dead,jump leads from good battery doesn't help ! Key seems fine - if I dry out the 2 footwell will this solve the problem ? Car is very wet inside as it was left for 3 months at side of house under a blocked gutter on the passenger side !! Interior lights work and dashboard central locking and headlights but nothing else ?
Dry it out with a heater inside or take out seat and carpets first??

 

[television]

I have not studied the 202, for 1998 there is only a little CAN and Not EIS orientated, I need to look a few things up on this one

 

[NW_Merc]

Hi sounds similar to the problem I,m having - see my post re "ignition key wont turn"
Both passenger side foot wells are soaking and car dead,jump leads from good battery doesn't help ! Key seems fine - if I dry out the 2 footwell will this solve the problem ? Car is very wet inside as it was left for 3 months at side of house under a blocked gutter on the passenger side !! Interior lights work and dashboard central locking and headlights but nothing else ?
Dry it out with a heater inside or take out seat and carpets first??

This will sound a silly question, but is there any power from the battery for the car to start?

If the battery is in good health, it may be best to take all the seats out of the car (it's pretty simple to do) then take the carpets out and let the car dry out completely. You'll also be able to tell where if at all the water has drenched through. Underneath the carpets there are sponge panels attached which will be holding water so it is best to remove them so that it dries properly.

 

[dermot dublin]

No power seems to be getting to ignition at all and key Wont turn it did start up about 2 weeks ago on a jump but battery is now completely dead - (6 mths old)

 

[television]

It could be possible that you have a controller leaking, you should not leave it in a discharged state as it will never be any good if left too long. Until you are sure that the battery circuits are all good, anything else is meaningless

 

[dermot dublin]

How do I test the circuits-I have a multimeter- but don't know how to use it properly- can u tell me where to test and what setting to have the m/meter at ? Thanks

 

[television]

You have a plastic cover ½ way along the nearside wing, under that cover there are charging points, you must make sure that you have 12 volts at this point, again the battery must be good, you can turn the headlamps on and there should still be 12vol minimum on this point

 

[dermot dublin]

Think I will dry the car out first ! Then see what the story is !

 

[NW_Merc]

When the car has dried out, I'd try a new battery rather than jumping the old one. If the car isnt used alot I'd also get a trickle charger hooked up the car to condition the battery when not in use.

 

[Adantiques]

Thanks for all the info and advice re.start of this post.My cars now alive and as it was before it got sick.Fault was as suggested water ingress in passenger side footwell messing with the electrics.My mechanic Basicly ripped out the interior and dried everything for a few days and checked/cleaned all electrical contacts.He cleared all the drains of the heater box and checked all the grommets underneath passenger/driver side for leaks.Hopefully it's now job done.