2005 XC90 Electrical System Saga
Junior Member
Joined: Aug 2013
Posts: 3
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Similar problem yesterday
I drove my wife to the Doctor's office yesterday. The car ran fine and exhibited no problems during the trip in town Upon leaving, I cranked up the car and noticed the gauges and A/C were dead in the water. In my case, the power windows and locks are working. In addition, the transmission appears to be slipping, as though it were stuck in a higher gear. We limped home and I searched the internet, found this tread and joined the forum.
In the past couple of months, the radio and CD player have had intermittent issues. The CD player broke and we chalked it up to age. More recently, the radio would not come back on after it was powered off. Eventually, it would power back up and we just didn't shut it off any longer
I followed the instructions in the thread and disconnected and shorted the battery. No help.....car behaving in the same manner. During the re-boot, I noticed the negative battery terminal was heavily corroded. Cleaned same. Does anyone have any additional information or updates on troubleshooting this problem. A wiring diagram would be great. Any help or suggestions would be appreciated
In the past couple of months, the radio and CD player have had intermittent issues. The CD player broke and we chalked it up to age. More recently, the radio would not come back on after it was powered off. Eventually, it would power back up and we just didn't shut it off any longer
I followed the instructions in the thread and disconnected and shorted the battery. No help.....car behaving in the same manner. During the re-boot, I noticed the negative battery terminal was heavily corroded. Cleaned same. Does anyone have any additional information or updates on troubleshooting this problem. A wiring diagram would be great. Any help or suggestions would be appreciated
Junior Member
Joined: Aug 2013
Posts: 3
Likes: 0
Similar problem yesterday
I drove my wife to the Doctor's office yesterday. The car ran fine and exhibited no problems during the trip in town Upon leaving, I cranked up the car and noticed the gauges and A/C were dead in the water. In my case, the power windows and locks are working. In addition, the transmission appears to be slipping, as though it were stuck in a higher gear. We limped home and I searched the internet, found this tread and joined the forum.
In the past couple of months, the radio and CD player have had intermittent issues. The CD player broke and we chalked it up to age. More recently, the radio would not come back on after it was powered off. Eventually, it would power back up and we just didn't shut it off any longer
I followed the instructions in the thread and disconnected and shorted the battery. No help.....car behaving in the same manner. During the re-boot, I noticed the negative battery terminal was heavily corroded. Cleaned same. Does anyone have any additional information or updates on troubleshooting this problem. A wiring diagram would be great. Any help or suggestions would be appreciated
In the past couple of months, the radio and CD player have had intermittent issues. The CD player broke and we chalked it up to age. More recently, the radio would not come back on after it was powered off. Eventually, it would power back up and we just didn't shut it off any longer
I followed the instructions in the thread and disconnected and shorted the battery. No help.....car behaving in the same manner. During the re-boot, I noticed the negative battery terminal was heavily corroded. Cleaned same. Does anyone have any additional information or updates on troubleshooting this problem. A wiring diagram would be great. Any help or suggestions would be appreciated
Thread Starter
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Junior Member
Joined: Nov 2011
Posts: 19
Likes: 2
I drove my wife to the Doctor's office yesterday. The car ran fine and exhibited no problems during the trip in town Upon leaving, I cranked up the car and noticed the gauges and A/C were dead in the water. In my case, the power windows and locks are working. In addition, the transmission appears to be slipping, as though it were stuck in a higher gear. We limped home and I searched the internet, found this tread and joined the forum.
In the past couple of months, the radio and CD player have had intermittent issues. The CD player broke and we chalked it up to age. More recently, the radio would not come back on after it was powered off. Eventually, it would power back up and we just didn't shut it off any longer
I followed the instructions in the thread and disconnected and shorted the battery. No help.....car behaving in the same manner. During the re-boot, I noticed the negative battery terminal was heavily corroded. Cleaned same. Does anyone have any additional information or updates on troubleshooting this problem. A wiring diagram would be great. Any help or suggestions would be appreciated
In the past couple of months, the radio and CD player have had intermittent issues. The CD player broke and we chalked it up to age. More recently, the radio would not come back on after it was powered off. Eventually, it would power back up and we just didn't shut it off any longer
I followed the instructions in the thread and disconnected and shorted the battery. No help.....car behaving in the same manner. During the re-boot, I noticed the negative battery terminal was heavily corroded. Cleaned same. Does anyone have any additional information or updates on troubleshooting this problem. A wiring diagram would be great. Any help or suggestions would be appreciated
In my case, the transmission was unrelated. I got Volvo to replace it for free after a lot of hand wringing.
Since the new transmission, CEM cleaning, and ICM change, the car has been working flawlessly and recently made it from Boston to Cape Breton Island and back without a glitch.
Good luck.
Dan
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Joined: Aug 2013
Posts: 1
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Dan your an absolute Legend!!!!
After spending hours upon hours syphoning through rubbish posted on the internet i stumbled on this forum! My only reason for joining is to praise the one person that has made any sense of the XC90 problems, Dan!
Your information regarding the CEM and ICM have assisted me rectifying a problem with a customers vehicle that has existed for 3 years! This vehicle has been to every electrician and dealership within a distance anyone was prepared to take the chance to drive it! I was the last chosen recommended repairer to have a go at fixing the problems starting with the repairs to the sunroof drain tubes? Then the CEM and now the ICM, noone could tell me the ICM played a significant role in any other electronics other than the radio? Your Knowledge has given me a direction not even the dealer could give me and for that i would like to say a big THANKYOU! Not to mention i`m now that little bit smarter
lol.
After spending hours upon hours syphoning through rubbish posted on the internet i stumbled on this forum! My only reason for joining is to praise the one person that has made any sense of the XC90 problems, Dan!
Your information regarding the CEM and ICM have assisted me rectifying a problem with a customers vehicle that has existed for 3 years! This vehicle has been to every electrician and dealership within a distance anyone was prepared to take the chance to drive it! I was the last chosen recommended repairer to have a go at fixing the problems starting with the repairs to the sunroof drain tubes? Then the CEM and now the ICM, noone could tell me the ICM played a significant role in any other electronics other than the radio? Your Knowledge has given me a direction not even the dealer could give me and for that i would like to say a big THANKYOU! Not to mention i`m now that little bit smarter
lol.
2004 XC90 Electrical issues
Have been reading this thread with GREAT interest.
Our 2004 XC90 has had tons of electrical issues and is now in the shop again since it will not start. Took it in to get the codes read, found lots, and when I left they all came up again. Took it back and now it will not start!
Have been getting the "thumps" out of the driver side dash then the dash fails, all the power accessories fail (doors, windows, AC, signals, etc) and the engine drops to lower gear. Was told this may be the DIM so had it replaced at a cost of about $2k. Still have the issue and am now being told it is the CEM that needs to be replaced to get the car to start again, repair the other failures, get the siren to work, the sunroof, etc.
Would appreciate it if anyone can give some guidance on steps to take to diagnose the issue then solutions on how to repair.
Background; have removed over 6 gallons of water from under the floor mats at least 2x, cleaned the sunroof drains, but still getting these failures especially when it is hot outside. Could the polling water have shorted out the wiring harnesses on the floor and now the water vapor in the harness is doing the same when its hot outside?
Also had the transmission replaced at a cost of $5k and got 50% back as part of a class action settlement, but am getting no info/guidance from Volvo on these electrical issues.
HELP!
Our 2004 XC90 has had tons of electrical issues and is now in the shop again since it will not start. Took it in to get the codes read, found lots, and when I left they all came up again. Took it back and now it will not start!
Have been getting the "thumps" out of the driver side dash then the dash fails, all the power accessories fail (doors, windows, AC, signals, etc) and the engine drops to lower gear. Was told this may be the DIM so had it replaced at a cost of about $2k. Still have the issue and am now being told it is the CEM that needs to be replaced to get the car to start again, repair the other failures, get the siren to work, the sunroof, etc.
Would appreciate it if anyone can give some guidance on steps to take to diagnose the issue then solutions on how to repair.
Background; have removed over 6 gallons of water from under the floor mats at least 2x, cleaned the sunroof drains, but still getting these failures especially when it is hot outside. Could the polling water have shorted out the wiring harnesses on the floor and now the water vapor in the harness is doing the same when its hot outside?
Also had the transmission replaced at a cost of $5k and got 50% back as part of a class action settlement, but am getting no info/guidance from Volvo on these electrical issues.
HELP!
Senior Member
Joined: Jun 2013
Posts: 200
Likes: 3
Looks like that definitely CEM.
Flash inside CEM is dying. When it's cold it works better.
Sunroof issue can be because if siren module.
Flash inside CEM is dying. When it's cold it works better.
Sunroof issue can be because if siren module.
Volvo XC90 2004 Electrical Issues
Volvo Sunroof Leaks – S40, S60, S80, V50, V70, and XC90 Vehicles - Chimicles & Tikellis LLP
I also am aware of a firm in Canada, XeMODex that offers a service for many vehicles to replace/repair electrical modules for less than dealer. Check out their services. I just sent my CEM into to them yesterday.
Good Luck!
Junior Member
Joined: Mar 2014
Posts: 1
Likes: 0
I suggest removing the CAN connector from the back of the ICM, the instructions for which are in another post of mine. If the dashboard starts working, you know your ICM is bad. I got a used replacement on eBay that's still going strong.
In my case, the transmission was unrelated. I got Volvo to replace it for free after a lot of hand wringing.
Since the new transmission, CEM cleaning, and ICM change, the car has been working flawlessly and recently made it from Boston to Cape Breton Island and back without a glitch.
Good luck.
Dan
In my case, the transmission was unrelated. I got Volvo to replace it for free after a lot of hand wringing.
Since the new transmission, CEM cleaning, and ICM change, the car has been working flawlessly and recently made it from Boston to Cape Breton Island and back without a glitch.
Good luck.
Dan
Danielle
Junior Member
Joined: Jun 2016
Posts: 1
Likes: 0
06 XC90 Going Crazy!
(06/20/2016)
Hello everyone!!! What a GREAT information here! Very helpful for a lot of us and maybe not. Well, less than two weeks I got me a 06 XC90, I bought it already acknowledged with the problems this baby was having. Very similar to you all.
1- Immbolizer see manual
2- Brake failure Stop Safely
3- Transmission Service Require
4- Passenger Airbag Off Service Urgent
5- Power System Service
6- Bad spark plugs and coils
7- Passenger seat goes crazy, it goes the appositive way when trying to move it
8- Sunroof intermittently working with the roof lights and a few others that I will be mentioning.
Ok, I started getting the CEM out, I cleaned, I noticed some rust on it and if someone had tried before pulling it out jamming some of the plastic. I had the battery recharged(the one with the car) but I was getting the same, cranking but wont start! Because of my work I can barely work on it the weekends, this past Saturday(06/18) I went and got a brand new battery( Interstate MTP-49/H8 ) as soon as I got to the car I connected the battery and try starting it, and it did started! YaY!!
I was so dam happy, my chest was pounding! I let it on while checking some other things around. Suddenly I started hearing like if someone was trying to crank it again, I thought maybe the key got stuck but no, so I went to the front of the car and indeed was coming from the started so I turned the car of. got the started out, I cleaned it, inspected and I put it again. Car wasn’t starting again! What I noticed on the dash is that when I turn the key to position II on the gear display all appears is —– and no light on the gear console. No power to the sunroof as of yet. I finished tightening and double checking on what I removed then after I tried again to see if it would start and it did. this time I got it out and drove it, went to put some gas and had it on for like two hours, everything appeared to work just fine but yet, no power to sunroof, no A/C kicking in, like a hour after I got it on, and driving it through the town, cluster went blank, I kept on driving it for one more hour or so, got home parked it on the garage, turned it of and then back on and everything was working just fine, sunroof got power, cluster illuminated and everything working just fine, I turned it off and on again and still everything just fine. I let it sat for the night, next day I got up concerned about the car turning on again and was the first thing I did to check on it and it did. (By the way, I did checked the siren and is working fine, starter too) So, later on that day(yesterday) again! wont start! I kept on playing with it, checked and cleaned almost all connectors on the engine bay and interior just to make sure, I still kept on noticing that on the gear selector, the light weren’t displaying the gear position, on the dash it was showing the position but if I were to move it, it would changed with delay, I hit and wiggle the CEM and the light/display on the gear selector got lit, turned the key and car started, got it out for a spin again, had id on for another two hours or so, while that time, A/C was working just fine, everything working, suddenly cluster went blank, no A/C but car stayed on, got home, turned off the car and tried it to started it again and it did. I let it rest for like half of hour, went back and tried it again and nothing, not starting. Any suggestions??? My next shot will be replacing the CEM and see if I have luck with that.
I will keep posting the progress. Thanks.....
Hello everyone!!! What a GREAT information here! Very helpful for a lot of us and maybe not. Well, less than two weeks I got me a 06 XC90, I bought it already acknowledged with the problems this baby was having. Very similar to you all.
1- Immbolizer see manual
2- Brake failure Stop Safely
3- Transmission Service Require
4- Passenger Airbag Off Service Urgent
5- Power System Service
6- Bad spark plugs and coils
7- Passenger seat goes crazy, it goes the appositive way when trying to move it
8- Sunroof intermittently working with the roof lights and a few others that I will be mentioning.
Ok, I started getting the CEM out, I cleaned, I noticed some rust on it and if someone had tried before pulling it out jamming some of the plastic. I had the battery recharged(the one with the car) but I was getting the same, cranking but wont start! Because of my work I can barely work on it the weekends, this past Saturday(06/18) I went and got a brand new battery( Interstate MTP-49/H8 ) as soon as I got to the car I connected the battery and try starting it, and it did started! YaY!!
I was so dam happy, my chest was pounding! I let it on while checking some other things around. Suddenly I started hearing like if someone was trying to crank it again, I thought maybe the key got stuck but no, so I went to the front of the car and indeed was coming from the started so I turned the car of. got the started out, I cleaned it, inspected and I put it again. Car wasn’t starting again! What I noticed on the dash is that when I turn the key to position II on the gear display all appears is —– and no light on the gear console. No power to the sunroof as of yet. I finished tightening and double checking on what I removed then after I tried again to see if it would start and it did. this time I got it out and drove it, went to put some gas and had it on for like two hours, everything appeared to work just fine but yet, no power to sunroof, no A/C kicking in, like a hour after I got it on, and driving it through the town, cluster went blank, I kept on driving it for one more hour or so, got home parked it on the garage, turned it of and then back on and everything was working just fine, sunroof got power, cluster illuminated and everything working just fine, I turned it off and on again and still everything just fine. I let it sat for the night, next day I got up concerned about the car turning on again and was the first thing I did to check on it and it did. (By the way, I did checked the siren and is working fine, starter too) So, later on that day(yesterday) again! wont start! I kept on playing with it, checked and cleaned almost all connectors on the engine bay and interior just to make sure, I still kept on noticing that on the gear selector, the light weren’t displaying the gear position, on the dash it was showing the position but if I were to move it, it would changed with delay, I hit and wiggle the CEM and the light/display on the gear selector got lit, turned the key and car started, got it out for a spin again, had id on for another two hours or so, while that time, A/C was working just fine, everything working, suddenly cluster went blank, no A/C but car stayed on, got home, turned off the car and tried it to started it again and it did. I let it rest for like half of hour, went back and tried it again and nothing, not starting. Any suggestions??? My next shot will be replacing the CEM and see if I have luck with that.I will keep posting the progress. Thanks.....
Member
Joined: Aug 2016
Posts: 49
Likes: 1
From: NY
Dem module symptoms
Interesting, so are you saying the DEM can cause crazy problems as described in this thread. I know all these modules are connected on CAN or MOST, but to think the DEM can cause unrelated issues is scary. My 05 XC90 is having weird issues and I have replaced almost everything to no avail, so does anyone have a list of symptoms that DEM can cause, and as you said, disconnect it, and this isolates problem?
I am new to Volvo's, been a BMW advocate for decades and never had issues like with Volvo's and beginning to question why I bought it as a back up winter vehicle. I would never have believed all these problems were possible without reading these and other forums. Freaking car is haunted and previous owner had the usual water tube blockage, filled up floor boards whenever it rained. I cleared them and am also considering pulling the CEM out until I read your tip.
Besides intermittent issues of engine dying, I can't get sunroof to work, went through the usual resets, three key turn, disconnect battery for hours, etc, did verify siren not working which kills sunroof, so pulled #8 fuse for siren, still no sunroof, pulled out control module for sunroof, checked for water damage, looked good, cleaned connector from switch ribbon cable, still nothing, so wondering, do motors go often. Put 12V to motor and nothing, so given this is difficult to get out with one bolt requiring cutting of head liner, I don't use sunroof, so can this being bad cause other stalling and loss of power issues. I know, makes no sense, but either did DEM being an issue on unrelated issues. Craziest vehicle I have ever worked on.
UPDATE: Turned out to be water leaking into CEM, pulled, cleaned with electronic cleaner and tooth brush, has white corrosion as leak existed for a while given sun roof drain plugs were clogged, plus the drain holes in wiper cowl were also clogged allowing water to build up to level it overflowed into CEM unit. Leaked through cable grommet, so you will have to clean out clogs, reseal grommet and top of cover over CEM. Been OK for months since finding problem.
Thanks,
I am new to Volvo's, been a BMW advocate for decades and never had issues like with Volvo's and beginning to question why I bought it as a back up winter vehicle. I would never have believed all these problems were possible without reading these and other forums. Freaking car is haunted and previous owner had the usual water tube blockage, filled up floor boards whenever it rained. I cleared them and am also considering pulling the CEM out until I read your tip.
Besides intermittent issues of engine dying, I can't get sunroof to work, went through the usual resets, three key turn, disconnect battery for hours, etc, did verify siren not working which kills sunroof, so pulled #8 fuse for siren, still no sunroof, pulled out control module for sunroof, checked for water damage, looked good, cleaned connector from switch ribbon cable, still nothing, so wondering, do motors go often. Put 12V to motor and nothing, so given this is difficult to get out with one bolt requiring cutting of head liner, I don't use sunroof, so can this being bad cause other stalling and loss of power issues. I know, makes no sense, but either did DEM being an issue on unrelated issues. Craziest vehicle I have ever worked on.
UPDATE: Turned out to be water leaking into CEM, pulled, cleaned with electronic cleaner and tooth brush, has white corrosion as leak existed for a while given sun roof drain plugs were clogged, plus the drain holes in wiper cowl were also clogged allowing water to build up to level it overflowed into CEM unit. Leaked through cable grommet, so you will have to clean out clogs, reseal grommet and top of cover over CEM. Been OK for months since finding problem.
Thanks,
Last edited by FREE-PPV; Nov 3, 2016 at 08:19 PM.
Junior Member
Joined: Aug 2016
Posts: 1
Likes: 0
Hi,
can anyone please help me or offer advice.
Firstly the transmission seems to be playing up by slipping into neutral and then the revs fly up and it engages back into gear with a big jolt?
Today the electricals stopped as well. The front windows, air conditioning, seat adjustment, am radio have all stopped working.
any advice would be appreciated. its a 2006 XC90 diesel
can anyone please help me or offer advice.
Firstly the transmission seems to be playing up by slipping into neutral and then the revs fly up and it engages back into gear with a big jolt?
Today the electricals stopped as well. The front windows, air conditioning, seat adjustment, am radio have all stopped working.
any advice would be appreciated. its a 2006 XC90 diesel
Junior Member
Joined: Nov 2016
Posts: 5
Likes: 0
While driving any distance over 60 minutes the car warning comes on saying sudden loss of brakes, stop safely. Airbag check light comes on. Within a few seconds all the electronics shuts down; all dash, stereo, lights, wipers, windows and lack of power to engine but car stays running. This was almost a deadly crash while driving in pouring rain and there were cars everywhere. No way to signal or flashers, I honestly thought me and my family were gonna get in an accident. I have read other stories online so my question is, What is the cause of this? How do I fix it before some gets hurt or even worse killed!I've contacted VOLVO and got no help. Been reading all sorts of things that"could" be causing this. I filed a complaint on the link below,there should be a recall on this. I own a 2004 xc90.
https://www-odi.nhtsa.dot.gov/VehicleComplaint/?
https://www-odi.nhtsa.dot.gov/VehicleComplaint/?
Member
Joined: Aug 2016
Posts: 49
Likes: 1
From: NY
While driving any distance over 60 minutes the car warning comes on saying sudden loss of brakes, stop safely. Airbag check light comes on. Within a few seconds all the electronics shuts down; all dash, stereo, lights, wipers, windows and lack of power to engine but car stays running. This was almost a deadly crash while driving in pouring rain and there were cars everywhere. No way to signal or flashers, I honestly thought me and my family were gonna get in an accident. I have read other stories online so my question is, What is the cause of this? How do I fix it before some gets hurt or even worse killed!I've contacted VOLVO and got no help. Been reading all sorts of things that"could" be causing this. I filed a complaint on the link below,there should be a recall on this. I own a 2004 xc90.
https://www-odi.nhtsa.dot.gov/VehicleComplaint/?
https://www-odi.nhtsa.dot.gov/VehicleComplaint/?
Good luck
Junior Member
Joined: Oct 2012
Posts: 11
Likes: 0
Module Issues
Agree this thread has been great and also concur that Heaviside Dan is the Man.
On the Module issue, my 2005 XC90 V8 was caught in rising water during Hurricane Irma. After drying many systems came back on line. Sill have SRS Airbag warning light, Radio powers on for 2 seconds only, and no driver power seat or sunroof.
Am thinking the CEM is in the loop and that will be my first stop. Due to the radio I was thinking ICM, but I have climate control and the 12V aux power, so that area was not a victim of water.
I also want to give a shout out to those Xemodex videos. They're very good.
I have not tried the extended battery disconnect, nor the shorting of negative to positive for a reset; which sounds scary to me. I'll need to see more documentation on that first.
I do not see where any vendor sells complete electrical harnesses. Due to sitting in water for a few days this may be necessary.
Would sure take any ideas on this as the Insurance Co is leaning towards a 'total' which doesn't make sense to me.
On the Module issue, my 2005 XC90 V8 was caught in rising water during Hurricane Irma. After drying many systems came back on line. Sill have SRS Airbag warning light, Radio powers on for 2 seconds only, and no driver power seat or sunroof.
Am thinking the CEM is in the loop and that will be my first stop. Due to the radio I was thinking ICM, but I have climate control and the 12V aux power, so that area was not a victim of water.
I also want to give a shout out to those Xemodex videos. They're very good.
I have not tried the extended battery disconnect, nor the shorting of negative to positive for a reset; which sounds scary to me. I'll need to see more documentation on that first.
I do not see where any vendor sells complete electrical harnesses. Due to sitting in water for a few days this may be necessary.
Would sure take any ideas on this as the Insurance Co is leaning towards a 'total' which doesn't make sense to me.
Junior Member
Joined: Feb 2018
Posts: 2
Likes: 0
How to totally disable MOST system without CAN system be affected
Some more info on this subject:
The car has two main networks--the CAN network and the MOST network.
The CAN (Controller Area Network) is implemented by connecting all the modules with a twisted pair of wires, one green and one white. The CAN has two parts, the high speed and the low speed. In general terms, the high speed network controls the vital functions--engine, transmission, etc. The low speed network controls most of the things inside the car--dashboard, climate control, Infotainment Module, windows, seats, etc.
The MOST (Media Oriented Systems Transport) is implemented by plastic fiber optic cable. It is limited to the entertainment system. If you look at the connections to the ICM (Infotainment Control Module), you will see both CAN and MOST connections.
All my problems were associated with a communication failure on the low speed CAN network. One weakness of this system seems to be that any one of the modules can fail in such a way that the entire network shuts down (high or low speed sides, not both at once unless it's the CEM). In my case, the ICM was hogging the network and not allowing the other modules to communicate. By disconnecting it and jumpering the connector as I described, I was removing that distraction and demonstrating to myself that all was good elsewhere.
Another weakness of the design seems to be this: even a dealership with the so-called VIDA computer system can have a hard time diagnosing a failure of this type. Because the network is overloaded with bad data, the VIDA computer has a hard time querying each module to see if it is healthy.
In my case, the dealership told me I needed a new DIM (Driver's Information Module--basically the dashboard), but the DIM was and is fine and was shutting down with the rest of the low speed CAN network. I saw a post on another forum in which symptoms similar to mine were caused by the DDM (Driver's Door Module). The DDM is attached underneath the window switches on the door and is apparently susceptible to water damage.
So, how do you know where to start? This is what worked for me.
First, do a hard reset. Turn off the ignition and remove the key. Locate the battery under the floor near the tailgate. Remove the plastic cover. Disconnect the negative (black) battery cable. Short the negative cable to the positive cable. I held it there with one jumper cable clamp. WARNING, be careful not to short the battery terminals--the negative battery terminal should be sitting happily not connected to anything. Leave it this way for about 30 minutes. This procedure removes all residual power from all modules resulting in a reboot--a little like taking the battery out of your laptop.
Now, turn on the ignition and watch the behavior carefully. In the short time before everything shuts down, the working modules will be attempting to communicate. In my case, the DIM was working, seats and windows were working, but the ICM never came up. Eventually, everything ends up where it started (dead), but, in the interim, you might discover where the problem lies.
Final thought: as a trained but not practicing electrical engineer, it is incredible to me how this system is designed. The radio taking down the whole car--are they kidding me? The way it should work is that the central computer should have the ability to turn off an offending module, display a message to the driver, and keep everything else going. Actually, you don't need to be an engineer to realize this--just someone with a brain--frustrating as heck after paying $55,000.
Hope this helps someone.
Dan
The car has two main networks--the CAN network and the MOST network.
The CAN (Controller Area Network) is implemented by connecting all the modules with a twisted pair of wires, one green and one white. The CAN has two parts, the high speed and the low speed. In general terms, the high speed network controls the vital functions--engine, transmission, etc. The low speed network controls most of the things inside the car--dashboard, climate control, Infotainment Module, windows, seats, etc.
The MOST (Media Oriented Systems Transport) is implemented by plastic fiber optic cable. It is limited to the entertainment system. If you look at the connections to the ICM (Infotainment Control Module), you will see both CAN and MOST connections.
All my problems were associated with a communication failure on the low speed CAN network. One weakness of this system seems to be that any one of the modules can fail in such a way that the entire network shuts down (high or low speed sides, not both at once unless it's the CEM). In my case, the ICM was hogging the network and not allowing the other modules to communicate. By disconnecting it and jumpering the connector as I described, I was removing that distraction and demonstrating to myself that all was good elsewhere.
Another weakness of the design seems to be this: even a dealership with the so-called VIDA computer system can have a hard time diagnosing a failure of this type. Because the network is overloaded with bad data, the VIDA computer has a hard time querying each module to see if it is healthy.
In my case, the dealership told me I needed a new DIM (Driver's Information Module--basically the dashboard), but the DIM was and is fine and was shutting down with the rest of the low speed CAN network. I saw a post on another forum in which symptoms similar to mine were caused by the DDM (Driver's Door Module). The DDM is attached underneath the window switches on the door and is apparently susceptible to water damage.
So, how do you know where to start? This is what worked for me.
First, do a hard reset. Turn off the ignition and remove the key. Locate the battery under the floor near the tailgate. Remove the plastic cover. Disconnect the negative (black) battery cable. Short the negative cable to the positive cable. I held it there with one jumper cable clamp. WARNING, be careful not to short the battery terminals--the negative battery terminal should be sitting happily not connected to anything. Leave it this way for about 30 minutes. This procedure removes all residual power from all modules resulting in a reboot--a little like taking the battery out of your laptop.
Now, turn on the ignition and watch the behavior carefully. In the short time before everything shuts down, the working modules will be attempting to communicate. In my case, the DIM was working, seats and windows were working, but the ICM never came up. Eventually, everything ends up where it started (dead), but, in the interim, you might discover where the problem lies.
Final thought: as a trained but not practicing electrical engineer, it is incredible to me how this system is designed. The radio taking down the whole car--are they kidding me? The way it should work is that the central computer should have the ability to turn off an offending module, display a message to the driver, and keep everything else going. Actually, you don't need to be an engineer to realize this--just someone with a brain--frustrating as heck after paying $55,000.
Hope this helps someone.
Dan
Thank you for all this info about CAN and MOST systems. Very complete info.
I need your advice please.
I got an XC90 D5 2005.
I would like to completely take out all the components of MOST system (fiber optic), and fit a classic system, by wires (central dvd screen, with two headrest screens, subwoofer with speakers and amplifier,etc.)
Do you have any idea how to do with the ICM? Because I need all the other components of the car (CAN system) to continue functioning, but not the MOST system components. So I need CAN system to continue functioning, and disable MOST system. Do you have any idea how to separate them in ICM? And I will use the double din space where is the small screen with the ICM now, to fit the new dvd screen instead. How to make it, so CAN system continue working?
Thank you
Junior Member
Joined: Jul 2020
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Shine
Hi all,
About the same time that my transmission started acting up, I began having electrical problems with my XC90. It started with radio/ICM intermittent behavior, and it progressed to a complete shut-down of the "low speed network". At this point, nothing inside the car works. You are in limp home mode, though the engine still works normally--no dashboard, no windows, no seats, no climate control, etc.
I read everything I could find on the internet (this forum and several others). I first investigated the CEM module for corrosion--had it big time. I removed the CEM, took it apart, and cleaned it with 99 percent alcohol and a toothbrush. When I put it back together, I had better behavior but not perfect. The low speed network would come up for about two minutes and then shut down again with messages about brake failure and airbags. The ICM was still dead, so I assumed there was still a problem there.
I disconnected the network connector on the back the ICM (green connector), and (big clue) the DIM (dashboard) came up and stayed up, but the driver's door didn't work. After studying the wiring diagram, I realized that disconnecting the ICM breaks the network ring. So, next I placed jumper wires on the back of the ICM connector (connect green to green and white to white).
Everything worked except, of course, the ICM. This gave me confidence that, if I replaced the ICM, I would be back in business. I bought one used (see another post), and all works now.
This was potentially a $3000 hit. Volvo wouldn't ante up. They did for the transmission, which was appreciated. This cost me a little under $300 and a fair amount of my time and effort, and I feel good about the result.
If anyone wants to pursue something like this and needs advice, let me know.
Dan
About the same time that my transmission started acting up, I began having electrical problems with my XC90. It started with radio/ICM intermittent behavior, and it progressed to a complete shut-down of the "low speed network". At this point, nothing inside the car works. You are in limp home mode, though the engine still works normally--no dashboard, no windows, no seats, no climate control, etc.
I read everything I could find on the internet (this forum and several others). I first investigated the CEM module for corrosion--had it big time. I removed the CEM, took it apart, and cleaned it with 99 percent alcohol and a toothbrush. When I put it back together, I had better behavior but not perfect. The low speed network would come up for about two minutes and then shut down again with messages about brake failure and airbags. The ICM was still dead, so I assumed there was still a problem there.
I disconnected the network connector on the back the ICM (green connector), and (big clue) the DIM (dashboard) came up and stayed up, but the driver's door didn't work. After studying the wiring diagram, I realized that disconnecting the ICM breaks the network ring. So, next I placed jumper wires on the back of the ICM connector (connect green to green and white to white).
Everything worked except, of course, the ICM. This gave me confidence that, if I replaced the ICM, I would be back in business. I bought one used (see another post), and all works now.
This was potentially a $3000 hit. Volvo wouldn't ante up. They did for the transmission, which was appreciated. This cost me a little under $300 and a fair amount of my time and effort, and I feel good about the result.
If anyone wants to pursue something like this and needs advice, let me know.
Dan
I had similar issues with the CEM and ICM with my wife's 2004 XC-90 about 5 years ago. Tried all the same things you did but it kept happening again. I finally found a repair tech in Toronto that gave me the solution.
First, there is a wiring harness tray under the windshield cowel. When the windsheild leaks the water goes into the tray, follows the wires right to the cntrol modules and corrodes and shorts them out. After buying dealer replacement parts, I found XEMODEX where they take your old modules and redo them and resend them back as 1/3 the cost of new. Mt service tech tried it and it worked and he now uses them for all his electric module replacements in Volvo, BMW. Audi, etc. Great company!
Second, you need to silicone the wires in the harness tray so if/when they get wet again, they will not carry the water to the new module(s).
Finally, we also have a sun roof in our model. The drain runs in the roof support into the passenger compartment inside the wheel well where it makes a 90 degree angle and exits the interior into the wheel well. The dirt from the sun roof clogs up at the at the 90 degree bend in the rubber pipe and leaked into the passenger and driver floor boards. I vacuumed over 6 gallons of water out of the floor area under the foam of the carpet. Of course that amount of water also runs along the floor into the back seat floor boards and the rocker panel where all the wires are run from the back of the car to the front. Result: water and electric don't mix so we had failures of the stabilizer causing the car to be hard to handle. We replaced the drain tubes, the 90 degree angle and also drill some weep holes in the floor boards and now if we get water, it drains before it gets too deep.
We reported this to Volvo of America and they have ignored us completely. There is a law firm in NJ that was creating a class action law suit but not sure what the final result has been. They also did a similar suit for the failing transmissions. Ours failed at 55k miles and we were told by Volvo of America that was the life of the transmission! We did get a $3,000 settlement for a $5,000 repair.
We still have the car as my wife loves the "safety" but she is considering getting another new car this year, and I am hoping she does not make another Volvo mistake! IMHO they are poorly engineered, poorly supported and expensive to repair and operate. My latest is an Acura MDX - parts readily available, reliable and more comfortable!
First, there is a wiring harness tray under the windshield cowel. When the windsheild leaks the water goes into the tray, follows the wires right to the cntrol modules and corrodes and shorts them out. After buying dealer replacement parts, I found XEMODEX where they take your old modules and redo them and resend them back as 1/3 the cost of new. Mt service tech tried it and it worked and he now uses them for all his electric module replacements in Volvo, BMW. Audi, etc. Great company!
Second, you need to silicone the wires in the harness tray so if/when they get wet again, they will not carry the water to the new module(s).
Finally, we also have a sun roof in our model. The drain runs in the roof support into the passenger compartment inside the wheel well where it makes a 90 degree angle and exits the interior into the wheel well. The dirt from the sun roof clogs up at the at the 90 degree bend in the rubber pipe and leaked into the passenger and driver floor boards. I vacuumed over 6 gallons of water out of the floor area under the foam of the carpet. Of course that amount of water also runs along the floor into the back seat floor boards and the rocker panel where all the wires are run from the back of the car to the front. Result: water and electric don't mix so we had failures of the stabilizer causing the car to be hard to handle. We replaced the drain tubes, the 90 degree angle and also drill some weep holes in the floor boards and now if we get water, it drains before it gets too deep.
We reported this to Volvo of America and they have ignored us completely. There is a law firm in NJ that was creating a class action law suit but not sure what the final result has been. They also did a similar suit for the failing transmissions. Ours failed at 55k miles and we were told by Volvo of America that was the life of the transmission! We did get a $3,000 settlement for a $5,000 repair.
We still have the car as my wife loves the "safety" but she is considering getting another new car this year, and I am hoping she does not make another Volvo mistake! IMHO they are poorly engineered, poorly supported and expensive to repair and operate. My latest is an Acura MDX - parts readily available, reliable and more comfortable!