I've got a 2013 Volvo XC90. Currently the Brake, ABS, Anti-Skid lights are on, the odometer is not functioning, and the trip meter goes to "-----" after about 10 seconds of turning the key on. There have been intermittent bizarre electrical quirks such as the brake light turning on in the middle of the night when the car is off, the key sometimes works to unlock/lock the doors, but often does not.
I've brought the car to a Volvo dealership and they said that in order to fix the brake, ABS, anti-skid issue they would need to replace the BCM. I replaced the BCM and nothing was solved. I brought the car to another dealership and they said that the CEM needed to be replaced. As you know, every time you bring a Volvo to a dealership it is a standard $2000 fix-whatever fee. I took out the CEM to see if there were any signs of the notorious moisture leaks through the plastic covering under the windshield wipers. The CEM looks brand new aside from a bit of dust on the exterior case. Inside the case, the CEM looks gorgeous. Not a sign of anything awry. I made sure to clean the board and contacts with electrical cleaner and gave the connections a slight coat of silicone dielectric compound to ensure conductivity and corrosion protection. I put it all back together and nothing changed. Lights are still on. The car runs fine. I followed Xemodex's flow-chart for testing the ABS...CEM and found no power going to the fuse #15. As you can imagine, I am hesitant to take this car to anyone else, because I'm getting all sorts of different opinions even from the dealerships with VICE...
So... I am worried that whatever I do with the CEM it will not fix the current issues and I am back at the beginning. These Volvo electrical problems are stunning given the price of these vehicles.
Any thoughts on what to do next?

 

common CEM faults are a) solder cracks causing open connections or b) failed relays internal to the CEM. You may need a wiring diagram to see how power gets to that fuse and if its from the CEM, then you may want to have Xemodex test and repair the CEM. The good news about Xemodex repairing an ABS controller or CEM is that they fix your original part so no VIDA programming is required.

 

If you get a diagnosis of a bad CEM - Have them replace it under the stipulation that if that does not fix your problems, your old one will be put back in and you will not be charged.

Or - find someone who can read all the codes with VIDA. Send your CEM to Xemodex with that list of codes and they can test your CEM. If there are problems with it - they can fix it.

 

Thanks for your thoughts. I’m curious if you have any idea which relays may tend to go on these things. I’ve done some diagnostic/repair work on circuit boards before, and I know that having an idea of what typically goes wrong can save a whole lot of time testing things.

 

Here's a common CEM failure - due to water leaks.

 

My CEM looks flawless. Really. There is absolutely no sign of water damage.

 

Or this one, plug looks not too bad, but corrosion on Integrated circuits. Have the car scanned with Vida, and get a print out of that scan. Any independents around that will do a 1/2 hour scan with Vida? You need codes to be able to formulate a diagnostic path. What part of the country are you?

 

If you have no power to pin 15, your CEM is not flawless. Appearance doesn't mean anything. It isn't powering a circuit it should. It needs to be replaced (or repaired)

 

ES6T
I understand looks aren't everything. Especially with circuit boards. My question now is what exactly goes wrong with these things. I have taken it apart and tested the relays. Two of the relays seem questionable. Are relays what goes wrong on them? Relays are mechanical and seem the most likely failure point, but I'm no pro... I'm just someone who was given a car that is way beyond my pay-grade and has a desire to know how the thing works...or doesn't.

 

Also, I have talked to folks on the phone who repair these things, and they have said, "Take it out of the case and see if you see any signs of water damage. If so, it's probably bad." So, I take that to mean appearance means something.

 

I don't know what goes wrong internally. I know that if the CEM isn't powering fuse 15, it needs to be replaced.