2005 XC90 No Power to Radio

[HereInOhio]

First I want to say thanks in advance for reading this! I was trying to get ahold of Clan but since I just signed up I cant PM and don't want to hijack someone elses thread.

I have a 2005 XC90 T6 I just bought and the radio doesnt work. I bought a replacement based on the ICM problems but it didnt work so I started from square one. First step was checking power and I didnt have it at the radio. I did have power at the fuses. I probed after the CEM and no power. Im someone who would prefers to look at a wiring diagram than buy parts to throw at it (I know my first move didnt support this). Based at what I am reading there could be a few problems:

- A relay that could be faulty on the CEM (wondering if this is IN the CEM and is transistors or if I can replace relays individually, I thought 2005 they are internal).

- Based on the last thing a faulty CEM.

- Normal function, read that if voltage drops below a certain spec it shuts off ICM. Im thinking this isnt it because I get no warning on the DIM although I bought it with a bad alternator (new battery) and the alternator is now new. It was dead due to leaving the glove box open and I currently have it on the charger and will double check power again since the initial time it was only a few hours after charging.

Also I bought DICE and it said no communication with ICM, could this be due to no power?

Last but not least can I just provide a power line with a fuse to the radio to get it going by bypassing the CEM if its the CEM? Hopefully you just didnt hurt yourself when you fell off the floor laughing at me for thinking Volvo would allow that.

Any help would be appreciated!

[HereInOhio]

So after some research it looks like if there is power at fuse #5 (ICM) on the CEM the relay is good and the CEM is providing power to the ICM. Is this correct?

I probbed the wire again and no power. I removed the connection "D" just above the red power wires from the CEM and it looked clean and I Ohm checked the wire/harness connection to make sure I'm checking the correct wire, I was.

I'm stumpped if this is the case, any suggestions?

My next step would be to remove the harness and prob the #3 pin in the CEM to see if power is there but I dont know what would happen running the car with that connector unplugged, anyone know?

[spokoluzik]

Try to give power to pin one(purple wire) and see if its any better. Closest will be cigarette lighter to get power from.
If its 2005 i would suggest to check cem itself.

[HereInOhio]

I will give that a try later. I was worried about putting too much power to it but I guess if it's 12v it should be ok. (I'm not the most familiar with current draw and supply and tread lightly especially with cars with all of the electronics.)

[HereInOhio]

I wanted to test the pin coming out of the CEM but didn't know what would happen if I ran the car with the CEM disconnected and if the radio would even be activated without the necessary signal inputs the other wires provides.

After disconnecting the battery to be safe I unplugged the D connector from the CEM and was actually able to take the D plug apart so I can have access to the rear of the ICM wire #3 connection. I actually took that wire out of the plug and hooked everything back up. With the engine running I probbed the CEM pin #3 and didn't have power. This told me power was going through the CEM and relay since it was at the fuse but wasn't making it from the fuse to the connector.

I jumped the power from the fuse to the ICM and it started working so that confirmed power was the issue. I was going to remove the CEM and send it to be rebuilt but can't justify the money for just the radio especially since I'm going to be selling it. I decided I'm going to leave the wire disconnected and plug an "Add-A-Fuse" from fuse #5 on the CEM and connect it to the wire in turn supplying power.

Thanks for your help and thank you to everyone who took the time to read my post.

[spokoluzik]

Sooner or later(probably sooner) your car very likely will die somewhere in most inconvenient situation if you leave CEM as is right now. You can also cause serious accident if your car will stop running at speed of 80-90 mph. No power steering no proper breaking power. Nothing at all. Can only imagine...
Imagine if you sell your car to mother with little baby on back seat and she crash during journey home. Would you ever fill comfortable with that???
If you don't want to spend any money for repair sell your car as faulty or at least remove CEM and clean all corrosion, then spray it with lacquer or something similar to avoid more damage to CEM.

[bemused]

did you ever resolve the issue with no power to radio?

I ask because I just bought an 05 XC90 T6 (from Cleveland, curiously) which had intermittent radio power. I swapped in an ICM with matching part number and now I have no power whatsoever to it.

[john langrick]

Hi, you probably have checked this, but is the MOST connector making a loop? I do know if this is broken your radio will appear dead. I learnt the hard way that the MOST bus is a pair of orange fibre optic cables.

You can buy MOST bus terminators on eBay, so with this you could isolate components.

For a start, unplug the cable from satnav ( if you have one) and you should see the orange light in the end of the plug on one side. The orange wires are the fibre optic cables. It could simply be that someone has kicked the cable out under the passenger seat.

Just a thought

[SwissXC90]

VIDA will tell you if you have a loop break and where it is!

So don't fire the parts gun at the car until you connect it to VIDA....

[foxhole]

Had radio which would turn off after 20 secs during colder weather , fine during summer months, I changed the car battery and everything work fine now,