Buying a used CEM and fitting
 

Hi all,

Following on from this thread - thought a new title would be best, for the next person who needs to search for CEM replacement! https://www.volvoforums.org.uk/showthread.php?t=277927

I found the CEM when I was replacing the pollen filter, pulled some fuses and the main connector plug, and can't see any water ingress around these, so really it needs to come out for a good look at the circuits - it's still just the interior lights which aren't working, as far as I can tell. They still come on for a second or two each time the ignition is turned on, before the CEM senses a short and turns them off.

I now have the part number for the CEM, 31314511 AB. Would it be a case of simply plugging this in, and going? I have VIDA so can tweak some settings etc. once plugged in, but would it need properly coding to the car? If it's simple, I might buy it (or a similar one), and if my original can be repaired, keep it as a spare.

https://www.ebay.co.uk/itm/VOLVO-XC6...torefresh=true

I assume you have a v70 or similar 2010 ish .

The Cem is the main computer for the car , it stores all the parameters, specifications security codes and immobiliser codes , mileage etc , You won't get a used one to work .
If you are lucky you can buy a new CEM for about £80 , unless your car is early , then it is around £600 for some reason .

If you have a problem with the interior light "shorting " I would concentrate on fixing that ..

Sorry, it's the 2012 XC70 in my signature.

It's logging code CEM-B1D1A12 Interior Lights Circuit "C" - General Electrical Failures - Circuit short to battery.

I've taken all the interior lamps apart and can't see anything amiss, the footwell and boot lights work as they should, so to me it seems like an internal CEM issue.

A new CEM for £80 sounds decent! Will that need to be set up by a dealer, or would I be able to with my own VIDA set up?

Have you fault traced interior lights ? CEM is the last thing on the list .. wires can get pinched .. yes a new CEM needs a reload software at a dealer , it puts back in what was in there before ...

I'll test out the wiring first, I have visions of most of the interior being dismantled and new rattles when it's all back together! It's my first time fault finding with CANBUS so I have a lot of learning to do...

Thanks!

My CEM is in Romford, Essex with a guy rebuilding it.

After much discussion, advice from people on here, reading stuff on other forums and a couple of conversations with people that know Volvos I concluded my CEM was knackered.

The CEM is paired with my car - probably with yours too I suspect. If it needs sorting there are 3 options:

1 - Pay a Volvo dealer to source a new one and transfer the data from your original - clone it (it's very expensive)

2 - Send CEM to the people I sent mine to - for a very reasonable £150 they will rebuild it and send it back with a 3 day turnaround time

3 - If the CEM is completely gone these guys will supply a reconditioned unit and clone it to yours for £330

I am just waiting for mine to come back.

My CEM is "Beyond repair".

Worse still I was informed that as it is an early model the software cannot be extracted for some reason. It has to be paired to the car in situ.

So, very helpful man has sourced me a reconditioned unit, my mechanic is fitting it then very helpful man is signing into a laptop remotely and is going to sort it for me.

Hi Alan,

Who did you send it to? Mine needs to go somewhere similar. An auto electrician recommended BBA Reman but they have terrible reviews!