In another of my threads I outline a bunch of electrical issues with my 2004.5 s40 2.4i. Cd changer constantly going, trunch latch constantly going, flashing of several different error messages on the dash, power steering coming and going every .2 seconds, etc...

My thought were that it was a bad rekay, as I can hear ticking coming from underneath the cover of the BCM (cabin fuse box) under the glove compartmemt. All of the fuses are good in that fuse box and the one in the engine bay. Another reason I think it's the BCM is that when u disconnect the fuse in the engine bay that establishes a connection with the BCM, the ticking/electrical problems stop.

Is this a reasonable prediction or could it be something else? Also, I have read that between 2004.5 - 2010, the BCM's are interchangeable between all the s40's and v50's, but figured I would check with someone more knowledgeable before purchasing a replacement.

Thanks!

 

That's not the BCM, so be careful when shopping for the part. It's the CEM. It is interchangable when new because it is programmed to the car. I've never put a used one it, but it may not work without programming and it also may be a total waste of money if it can't be rreprogrammed.

 

My first reaction on any "my car's going crazy" post is battery.

• How old is yours?
• What is the resting voltage?
• Are the battery posts bright?
• Are the inside of the lamps bright?
• Are the cable attachments to the frame tight?

 

I plan on testing the CEM using instructions from this postVolvo S40: how can i test the central electronic module?). I was wondering if anyone else had any methods to test for a bad CEM or BCM.

As far as the battery goes, the initial thought was that the battery was the issue, but we've dismissed that. Standing voltage is a little more than 12V, on crank a littme more than 14V. Cleaned the battery posts and make sure all cables were tight/not frayed. The other reason we believe it may be something else is because there is a leak on the driver side, leading to soaked floors in front of and behind the drivers seat.

 

I have seen reports of successfrom cleaning CEM contacts in such cases. They are multi-contact connectors that can be sensitive to corrosion. As you probably already know, disconnect the battery before you climb under the dash, though! (The battery fix worked for me.)

 

I will definitely try that and update the thread if it works.

Thank you for your input!

 

So after about 2 hours of searching I cannot for the life of me find the CEM. Every single picture/thread related to it show it in relatively the same spot next to the steering wheel, but for the 2004.5 s40 2.4i, I haven't been able to find any documentation/pics/etc. Any ideas as to where I may find this?

 

the Gen 1s are under the steering wheel (right above the hood release). I believe the Gen 2s are below the glove box.