Augusta, Ga, Need help getting to the CEM XC90

red-devil · Post by **red-devil** » 26 Jan 2012, 10:14

My problem is that my brake lights are on every time I start my 2006 XC90 2.5T and I get a "Check Stop Lamp" message. If I turn the key to postion I, there is no indication of a problem. From information that I have found online the CEM for my XC90 might have gotten wet and corroded due to a bad design on the housing letting water in. I would like to be able to get to the CEM clean off any corrosion and to better seal off the housing.

TERINASSsydwayz · Post by **TERINASSsydwayz** » 06 Feb 2012, 08:26

Hey Red-devil. I'm Jesse and i live in Evans - i would be happy to lend another set of eyes to your problem and see if we can do something about it. I don't have any specific knowledge about your problem but check your PM's for my info.

Post by **jimmy57** » 06 Feb 2012, 08:56

You will need to remove the wiper arms and then the cowl cover in order to get to upper CEM connectors. The box you will see in front of driver under that cowl cover is the connector cover for the CEM on the top side.
The CEM has connectors on the CEM body inside also.
The top cover is the place where water can get in but it is usually an ice dam problem where ice blocks the drain and gets high enough to run into CEM cover. I guess leaf/debris accumulation could give the same issue.

TERINASSsydwayz · Post by **TERINASSsydwayz** » 07 Feb 2012, 08:10

so Google reveals this could be the "tip of the iceburg" which can be followed or accompanied by all systems shutting down while you are driving or other fun things like being locked out/in.
The 1st fix appears to be access - removal - assessment - clean - protect - reinstall

In searching i came across ECU pin cleaning suggestions of WD40 with toothpicks and cotton swabs. A person did make a very compelling argument for the use of a product called Jiffy Bath which dissolves corrosion and seals with protective oils.

So get some Jiffy Bath from radio-shack or find some around here, a tube of di-electric grease, and the access instrucions and diagrams and we'll see what we can do ~ and of course we can document it for MVS contribution.

red-devil · Post by **red-devil** » 07 Feb 2012, 17:06

TERINASSsydwayz wrote:so Google reveals this could be the "tip of the iceburg" which can be followed or accompanied by all systems shutting down while you are driving or other fun things like being locked out/in.
The 1st fix appears to be access - removal - assessment - clean - protect - reinstall

In searching i came across ECU pin cleaning suggestions of WD40 with toothpicks and cotton swabs. A person did make a very compelling argument for the use of a product called Jiffy Bath which dissolves corrosion and seals with protective oils.

So get some Jiffy Bath from radio-shack or find some around here, a tube of di-electric grease, and the access instrucions and diagrams and we'll see what we can do ~ and of course we can document it for MVS contribution.

I'm not sure where to find the instructions on how to remove the CEM from the cabin, but I am able to get to the top of the box under the cowl. Hopefully it's easier than it looks. Are there any websites that would have the diagrams?

TERINASSsydwayz · Post by **TERINASSsydwayz** » 17 Feb 2012, 13:33

hey guys! we are trying to get this thing out and we seriously cannot get it to come out! anyone with pictures of how to take out the CEM box(s) please upload or give some brother's some helpful suggestions!

TERINASSsydwayz · Post by **TERINASSsydwayz** » 17 Feb 2012, 15:53

will update with pics and writeup - we got it out and are servicing it.

TERINASSsydwayz · Post by **TERINASSsydwayz** » 17 Feb 2012, 21:15

So Red-Devil and i were able to fix his erratic brake-lights by pulling the CEM out from under the dash, disassembling it, cleaning it and putting it back in. Some snags we hit along the way were finding out how to successfully remove the cem. Underneath the dash the Unit sits in a bracket and is held in place by 2 size 25torx screws at the leading edge of the unit and bracket - undoing these will allow you to work the very obvious pivot mechanism holding the entire CEM housing and unit in place. Those 2 torx are accessed from above by using an extension through the wiper area and are very hard to see with the naked eye, a mechanics mirror will come in very handy here.
We did not find these torx screws until we removed the bracket and housing as a whole piece which was done by very, agonizingly slowly, removing the 2 8mm bolts that secure the bracket to the support from the frame. There is very little room to maneuver and the approach is completely blind from above the box and against some insulation/padding that rests against sheetmetal. I do not think these bolts were ever meant to be tampered with like this but my hands hate me and the jobs done.
After the CEM housing was removed we took it inside and took of the shielding/cover to find a dirty board with alot of mild to moderate corrosion - after seeing the board and reading all the other problems this can cause i can't believe it has caused so few problems. The board was cleaned with "electronics cleaner" and the deposits were 'liberated' with toothpicks and a tooth brush then cleaned again and cleared with canned air. Dielectric grease was thinly applied with a gloved fingertip, toothpick and cleaned toothbrush and difficult globs were blown thin with air. the whole housing was wiped down and resealed.
When reinstalling, the bracket was placed into position and then the 2 8mm bolts were driven UP through he hole to make the upper bracket holes lay over the exposed studs - this give good "downward" stability. We just could not get the bolts back in from the top. Through the upper access hole the bracket was held with downward pressure in place and the cem was pushed up into place and secured with the 2 25torx screws, then the lower "lobe" of the casing just above to fuses was surrounded by a few zip-ties and tension was applied toward the frame rail directly across from the 'yellow' plug. this tension keeps the whole thing in place and then everything else was reinstalled normally without real incident.

Follow these pics and their descriptions in this album to see a little about what we were working with. GooD LucK!!

photobucket.com/xc90cemrepair

<div style="width:480px;text-align:right;"><embed width="480" height="360" src="http://static.pbsrc.com/flash/rss_slideshow.swf" flashvars="rssFeed=http%3A%2F%2Ffeed5.photobucket.com%2Falbums%2Fy156%2Fjvladamir%2F2006%2520Volvo%2520XC90%2520CEM%2520removal%2520and%2520repair%2Ffeed.rss" type="application/x-shockwave-flash" wmode="transparent" /><a href="http://photobucket.com/redirect/album?showShareLB=1" target="_blank"><img src="http://pic.pbsrc.com/share/icons/embed/btn_geturs.gif" style="border:none;" /></a><a href="http://photobucket.com/xc90cemrepair" target="_blank"><img src="http://pic.pbsrc.com/share/icons/embed/btn_viewall.gif" style="border:none;" /></a></div>

TERINASSsydwayz · Post by **TERINASSsydwayz** » 17 Feb 2012, 21:22

I dont know how to embed the album. ^^^^^^^ that was the code PB gave me

oh well the link works

red-devil · Post by **red-devil** » 18 Feb 2012, 07:16

Hopefully today I will be able to post pictures from under the cowl. The amout of corrosion on mine was minor compared to others that I had found online, it looks like the CEM is very sensitive to any amout of moisture.