General: XC90 2005 2.4 AWD CEM probs?

[musicjoka]

Been having a few problems with my XC90 over last few months and have read many threads that could be related but would really appreciate any feedback on the following.
I live quite remote and it is a 250 mile round trip to nearest Volvo Dealer (might not be a bad thing ;-) ) .
I have a very good local ind mech who has looked at my car and advised me I may need to head to Volvo.
Here goes
Had anti skid message last year and diagnostics showed faulty sensor which was replaced. All fine for a few months then on starting car one day lots of warning lights and messages. Car very slow on pick up but would drive ok. I took it to nearest local garage and on diagnostics they said there were numerous errors and they didn't know where to start ! NOt much help.
On drive home everything seemed to settle down and car drove ok for the next while so thought it was some sort of blip that had corrected itself although the anti skid warning was still present.
I then noticed that the AWD was deffo not working and then the brake assist message appeared and the ABS warning light was on.
Took it to my usual mech and on diagnosis he gets this
1A64 Communication with the DEM, signal missing
0094 Communication between control modules : communication problems with active on demand couplings

Having trawled through all of the feedback on these issues I can find, it would be useful to know the following if anyone can help
1 Is this a CEM problem ?
2 Is this a DEM problem ?
3 Is it both !! ??
4 Is it likely to be something else ?


I understand these modules can possibly be re conditioned. Would it be worth removing it/them and sending them off or better to do the 250 mile round trip to have Volvo look at it??

HELP PLEASE

[Acer]

Originally Posted by musicjoka

Been having a few problems with my XC90 over last few months and have read many threads that could be related but would really appreciate any feedback on the following.
I live quite remote and it is a 250 mile round trip to nearest Volvo Dealer (might not be a bad thing ;-) ) .
I have a very good local ind mech who has looked at my car and advised me I may need to head to Volvo.
Here goes
Had anti skid message last year and diagnostics showed faulty sensor which was replaced. All fine for a few months then on starting car one day lots of warning lights and messages. Car very slow on pick up but would drive ok. I took it to nearest local garage and on diagnostics they said there were numerous errors and they didn't know where to start ! NOt much help.
On drive home everything seemed to settle down and car drove ok for the next while so thought it was some sort of blip that had corrected itself although the anti skid warning was still present.
I then noticed that the AWD was deffo not working and then the brake assist message appeared and the ABS warning light was on.
Took it to my usual mech and on diagnosis he gets this
1A64 Communication with the DEM, signal missing
0094 Communication between control modules : communication problems with active on demand couplings

Having trawled through all of the feedback on these issues I can find, it would be useful to know the following if anyone can help
1 Is this a CEM problem ?
2 Is this a DEM problem ?
3 Is it both !! ??
4 Is it likely to be something else ?


I understand these modules can possibly be re conditioned. Would it be worth removing it/them and sending them off or better to do the 250 mile round trip to have Volvo look at it??

HELP PLEASE

If your AWD is bust and there is a DEM message present then I would say that is your problem. Anti skid is linked to the AWD system also and that message can appear for a number of reasons I believe (Yaw sensor issue, DEM problem etc.)The messages suggest communication issues associated with the AWD system and that could be because the DEM itself is bust or there are issues with messages being sent to and from the DEM to the car's brain.

I will be honest this could be pricey to fix. A new DEM is something like £1000 just for the part, but i think it is possible to get one from the same model year and it will work. Someone else can probably confirm that. On a positive note I don't think any of this will render your car unusable. You just won't be much good on a ski slope .

If it was the CEM at fault then I would say buy a new one, but defo worth trying to get the DEM fixed (it is a very basic looking thing once the shell is off!) if you can. It is easy to take the DEM off and it resides towards the rear underside of the vehicle.

[musicjoka]

Thanks for the reply ACER.
THe car is driving fine at the moment and yes I will be staying away from ski slopes !! No AWD.
I think my best option is to remove the DEM and see if it has a fault and can be fixed - BUT
I am sure I read on a thread somewhere that a faulty DEM will not trigger an ABS warning light - anyone know if this is true ?

[bobdabuilda]

Search for my extensive posting on this experience on the forum and it'll give you all the info you need. The DEM is plug and play and contrary to what the dealers say is not coded to the car. BBA REMAN now do DEM test/ repairs and it will be a fraction of the cost of a new unit. I was lucky to source a brand new one from Poland for a fifth of the cost of what Volvo UK wanted but that was pure luck. You'll also need to check the pressure sensor and abs pump /filter as part of the workup. Good luck!

[rsymes2k]

+1 for sending the DEM to BBA Reman

[byrlord]

Originally Posted by bobdabuilda

You'll also need to check the pressure sensor and abs pump /filter as part of the workup. Good luck!

Hi, why and how to check the abs pump / filter?

Thanks in advance.