Several months ago, my XC90 started acting up. During long drives, the engine and electronics would suddenly shut off for a second, and return to its normal state, giving the car a big jolt in the process at high speeds. This happened several times at high speeds and low speeds. Now, the car is at limp mode (electronics do not work, no instrumentation, but can drive the car on limp) with the check engine light on. Turned the car off and back on, and it always stays on limp mode. The following errors codes have been read: P0863, U0073, P0504, and P0571. I then disconnected the battery and removed the CEM to check if there was any type of corrosion on the CEM, but it seems like there isn't any.

Could it be one of the other modules that is the problem? Could my CEM be overheated? My A/C hasn't worked for a couple of years, and the driver's side controls do not work as well (driver's side window, driver's side mirror, and driver's side door lock) due to water seeping through the driver's door window. Does anybody experienced the same issue(s)? Please advise.

Thank you.

 

Sorry for the late reply but yesterday after picking up my wife i had the same issues and codes. I googled and researched the issue and was looking into a new cem around $600 programed. Most posts were talking about a overload in power to the cem being at fault. I thought about it over coffee this am and went and checked the fuse for the cem which is a 10a fuse. Looked well used so replaced it. Started my car up amd all dash gauges etc were good. I erased the codes, drove around and checked again with no codes appearing. Ill drive it around for the next few days and see if it comes back but could ve the issue/fix.
Dont know of your fixed yours but Ill leave this here in case anyone comes accross this problem and finds this to be the fix. You know $2 vs $600 is a huge difference. Hope it works and helps anyone in the future.

 

If it does turn out to be the CEM, there are services like Midwest ABS and XeModex who will rebuilt your unit to avoid the programming costs.

 

My '04 XC70 had this yesterday. Exactly the same codes

Vida showed a strange "disconnected box" with a battery and key symbol top right.

I pulled the 32 fuse which caused the alarm to go off. When I pushed the fuse back in, the alarm went off, and everything was back to normal. I cleared the codes and now have full functionality.

I wonder how many people bought new/refurbished CEMs because of this

Will report if it comes back. I suspect the door lock/alarm system