Hi all, there seems to be a lot of small threads about the central locking not working with various outcomes. I'm going to try and get a thread together where any future problems can be solved by reading this one thread.

so my 05 UK convertible crossfire central locking won't work from the fob.

I get no flashing lights and lock and unlock do not work from the key.

the central locking button on the dash operates both doors, both locking and unlocking.

so far I have checked for water damage to the pump in the boot and it is dry and all locks work with the dash button so I'm happy it all works.

my fuse 9 is fine and all interior lights work ( common problem)

my alarm siren had a short and had melted the connector block so is now unplugged.

my thinking is now down to one of 3 things

1. key is not sending lock or unlock signal

2. Skreem is not receiving the unlock signal from the fob

3 The body control module is not getting a signal from the Skreem to send to the central locking pump to unlock/lock the doors.

so I'm thinking of a few options.

1.Getting a second hand kr55 key and moving the transponder chip and blade over and trying to sync it to the car.



2. Replacing the skreem. (can we use a second hand one?)

3.Replace the bcm ( can we use a second hand one)

4. replace key, drivers door lock, skreem and bcm from a breaker.

If we can all try and keep speculation to a minimum and just post actual experience it will hopefully make for a good sticky for the future.

and hopefully I will fix my central locking
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The answer to #2 is NO. You can not use a second hand SKREEM module. It is Vin specific. Needswings.com is going to be the best option if you find yourself in need of this unit.
#1 is a viable option, proceeding with the way you mentioned. If you do want to get a second key (peace of mind), again Needswings has, prompt, reliable an good turn around time ,on this issue.

 

So how are you meant to change it then Steve? Do you order one according to the vin and it's flashed accordingly?
I believe the bcm is vin specific as well?

Also, does anyone know the actual sequence of events from when the fob buttons are pressed? Ie, which component receives the signal from the fob and how is it actioned after that point.

The wiring diagrams don't always help either. For example, when fuse 9 is blown, the locking won't work, but according to the diagrams, fuse 9 is not related to the locking?
I think it does send a feed to the bcm, but what for? Maybe to a volt free contact, but its not obvious after that. It seems their system is hugely over complicated.

I think No1 is the first to try as well.
When my locking failed, the indicators on the car would still flash when you pressed the fob buttons - inferring that the fob is sending a signal and the car is receiving it.
When Lyndon uses the fob, the indicators don't flash.

 

Ok,

After another look, I found the following:

Fob sends a signal to a receiver (Z87/15) behind the dash near the airbag, this connects to the radio frequency DAS control (N54/3) via terminals 6&7. DAS control is behind the instrument cluster. DAS then talks to the bcm, which then talks to the PSE control module (air pump assembly), which then signals the indicators to flash and send air to the relevant locks.

Lyndon,
I know you've checked the PSE in the boot and it seemed ok. Did you pull the multiplug connectors off it and have a look at the terminals? That PSE appears to carry out more functions than we may give it credit for. In saying that, I'm still suspecting that the fob may not be sending out a signal to the receiver.

 

The fob signal is received by the SKREEM which signals the BCM to signal the CLP/SSM to operate the appropriate lock(s).
The CLP/SSM does indeed do a lot of functions we forget about or do not realize.
The red indicator in the fob lights briefly when a button to lock or unlock is pressed, you have to be in a dimly lit area to see the flash.

 

Your correct - I was looking at the wrong wiring diagram....... so your sequence is correct. I must name my diagrams, I was looking at an old R170 one...Doh!

Edit.

I just looked at the diagrams in your pdf, which shows the sequence I suggested?

 

The BCM can be replaced from a donor, BUT, has to be EXACT numbers matching, from what I understand. You can't put one from a SE into a Limited or Limited into Convertible an so on. From what I've read, doing so causes, small but significant quirks to appear , i.e. spoiler works , but not from the console switch (no manual deploy). I haven't done this ,it's what I've researched, because my window switch failed to work one day. Search " repairing the BCM".

 

Hmm,

I think some things are just being called different names. What they call the radio frequency DAS control (N54/3) - is what we are calling the skreem module...
And what they call the multifunction control module, we are calling the bcm - doesn't help I suppose.

 

Thanks for all the replies, sorry i haven't replied earlier.

I have just tried to sync a Mercedes key and no joy.

I'm now at a crossroads, do i replace the skreem or the bcm?

Im guessing at replacing the skreem as it would appear that the car is not receiving the signal from the key.

would there be any other symptoms of a bad skreem? i dont get my flashing indicators when i lock the doors manually. is this normal?

sorry for all the questions. all the help is greatly appreciated

 

Symptoms of a bad SKREEM is usually, 3 attempts at starting then nothing, remove battery cables, reset an same results.

 

That's really useful thanks

 

I've heard 1 success story on a FOB that wasn't "for the car" ... the forum is full of cases of ebay fobs not syncing up.

 

Difficult one eh?
It could indeed still be the keyfob.
As far as I'm aware, the indicators should always flash when using the remote. It's telling you the fob put out a signal and the skreem received it.

I still think it could be a fob issue, but don't really know where to go from here now. The skreem is a sod to get to, so you don't want to be replacing it until the fob issue is 100% ruled out I suppose.

 

Maybe it's worth getting a keyfob tester. At least that will rule it out? - or not.

https://www.ebay.co.uk/itm/Sealey-IR...-/381471900830

 

The read light flashes dimly for less than a second and shows that the battery is OK. That does not necessarily mean that there has been a signal emitted.
It is a battery tester and that is all the way the books read anyway.

 

I mean the indicators (turn signals) on the car should flash when using the fob....

 

Both fobs acting that way ? If only one key did you replace the batteries (two 2025s AFAIR) ?

 

He only has one fob and has tried batteries, re-sync etc.

 

How about the relay In the under hood fuse box.. the one we attach buzzers to? Back of my mind seems there was a case this was the issue..

 

Well just one fob makes it harder. Have you tried holding the fob inches from the car and moving all around the car while clicking. Could be an antenna issue & not sure exactly where the antenna is in yours.