Central Electronic Module (CEM) question
 

I have a 2006 V50 that I just replaced the Central Electronic Module (near passenger feet) in because I found water intrusion when diagnosing a no start. The car still will not start. Does this module need to be programmed? And if it does, can it be programmed multiple times (I got this used off another car).

Yes, the dealers will have to code it. Have you purchased a second hand one or is it new? As far as I’m aware, once they’re coded, they can’t be coded again. Speak to your local dealer.

TT

I had same problem, took off cover to evaluate, a lot of white corrosion was visible, so bought some electronics cleaner, got tooth brush and cleaned all areas of corrosion, always on top PC board in my experience, put it under heat lamp to dry out, solved problem of no starting.

When you replace with used CEM, you could be adding problems, but dealer will need to recode.

Good luck,

A quick how to clean your CEM link

https://ozvolvo.org/discussion/5649/...ctronic-issues

Thanks for the replies guys. I will try cleaning it myself. I did take it apart and saw the corrosion was pretty bad but I'll try cleaning. If that doesn't work, do you know of somebody that it can be sent off to to get fixed? I know there are companies that do it for things like gm gauge clusters. I just hope it's the only problem cause the only thing on the gauge cluster that works is the check engine light. The radio doesn't work and the hvac is hit or miss. Also won't try to start.

You will solve most of these ghost haunting problems by simply thoroughly cleaning corrosion which is easy to see as you found out. Concentrate on those areas, and push tooth brush and electronics cleaner under all connections and IC chips on top PC board which is ironically the only PC board which isn't coated in plastic dip and the one most exposed to water damage. Crazy, but then again, Volvo's are made to break down so you have to go back to dealers. lol Make sure you correct water issue, cowl drain tubes get blocked along with sun roof drain tubes, so then seal top of CEM with some good silicone sealer.

Good luck,

I'll give it a try this weekend and report back. Thanks for the help!

I took the CEM apart and found corrosion on the inside. I was able to clean all of that off. Car still won't start but has less codes. The cide thats keeping it from starting is 720A whuch is an immobilizer code. I cant dind much indo about diagnostics for the code though. If anybody has a diagnostic procedure for this code that would be awesome.

Thanks to FREE-PPV. When I took the cover of my CEM off I saw just a bit of corrosion. I cleaned it off with methyl hydrate and a toothbrush then I applied some dielectric grease to prevent further damage. So far it's working just fine.

Transfer the chip
 

Just wanted to put this here:
If your CEM is ruined you can buy a used one cheap on eBay and get someone skilled at soldering to swap your chip onto the board, I paid $40 for the new used CE? and $50 for the work.
As far as I know, no one has found the source of the leak. I packed absorbant material above the green connector to catch it.

XeModex will rebuild them as well. They also have some trouble shooting info on their site

There's a couple of ways to deal with it. Buy a new CEM and have it programmed at the Volvo dealer or Independent that is capable. The other is to send your old one to XEMODEX. Read all of their info regarding P1 CEMs.
Central Electronic Module for Volvo | XeMODeX Inc.

better solution and the big question
 

If you buy a used module, I figured out you can remove the main chip from your old board, and solder it to your new one. I had a local guy do it for $50
Also, did anybody ever pinpoint the source of the leak? I've only heard speculation.