My 07 XC70 being held hostage.

[Madijain-]

Greetings-
I am reluctantly posting because I know nothing about Volvo's and desperately seeking advice because I know nothing about Volvo's.The facts are as follows. I bought a 2007 XC70 with 125,000 miles. One owner, custom order, bells, whistles, perfect condition and excellent service records. Now, one year later the vehicle has been out of commission for the past three months. Coincidentally, shortly after having brakes replaced at a Volvo Dealership.
*First and only OBDII codes pulled:
Camshaft Intake Position Sensor - Replaced at non-volvo shop
Transmission Sensor/Wheel Speed Sensor - Replaced at non-volvo shop
Serial Comm. Link Malfunction -
Control Module Internal Fault -
Received vehicle from (non-volvo) repair shop with no warning lights or messages. Had the vehicle in my possession for less than a day when the dash lit up like the Fourth of July!. Towed it to a different Volvo dealership for better diagnosis capabilities. Dealership suggested BCM (thank you XemodeX) replacement. I expressed to the Volvo dealership that I didn't believe the problem was the BCM but reluctantly agreed to replace it because my options are few. Dealership now claims ten new codes have been found since replacing and uploading new BCM!! The commonalities, I see in the later two, reappearing codes are the CAN BUS and the ECM, neither of which are cheap.
*The vehicle warning messages prior to dealership :
Brake Failure Stop Safely
Anti-skid Temp. Off
Spin Control Off
Immobilizer Active
Transmission Service Required
Engine Service Required
Tire Pressure System Service Required
*Vehicle symptoms were:
May or may not start
May or may not continue to run once started
May or may not make it to a desired destination
Rough engine and stalling
Poor excelleration and fuel mileage
Warning light and messages may or may not come on at start
Warning lights and messages will come on when driven a short distance

Please, sweet baby Jesus, is there anyone that can make sense of this?!?!? I am rapidly losing brain cells and I suspect the dealership may be trying to take advantage of my serious lack of Volvo knowledge.

[vtl]

Some high-speed CAN bus module failed. Often it is CEM. Find a good car electrician.

[Madijain-]

Some high-speed CAN bus module failed. Often it is CEM. Find a good car electrician.

Thanks for the response, vtl.
So, this would be an automotive electrician above and beyond the Volvo diagnostician/mechanic?
I just got off the phone with the Volvo mechanic he said there are no codes miraculously showing after a test drive. However, this happened to me a few times too, only to be left stranded when the vehicle decided to cough up some codes and die. Is that typical failure behavior for a CEM?
Go Pats - I hail from Maine!

[JRL]

Have you replaced your battery?
These cars do not do well on old, original batteries after 9 years! (and they throw many codes and can have really odd symptions).

[precopster]

I second the CEM diagnosis however a careful check of the alternator prior to any work being done. What voltage is the alternator producing at idle. Get the alternator checked for AC leakage by a reputable auto electrician. While you're there it wouldn't hurt to check the battery. The CEM is not cheap to repair and if replaced, will require programming to your vehicle. Again XeModex can help.

[vtl]

So, this would be an automotive electrician above and beyond the Volvo diagnostician/mechanic?
I just got off the phone with the Volvo mechanic he said there are no codes miraculously showing after a test drive. However, this happened to me a few times too, only to be left stranded when the vehicle decided to cough up some codes and die. Is that typical failure behavior for a CEM?

Electrician who knows P2 Volvo is preferable, of course.

The car has two CAN buses: high-speed and low-speed. HS is for communication between critical units, like engine, transmission, brakes, and LS bus is for the rest, "convenience" units. Central electronic module (CEM) sits on both buses and acts as a bridge (and also does other things). When it fails it may cause communication failures on HS or LS buses or both. CAN bus is not very well protected against malfunction: any failing device can knock the entire bus down.

Here's xemodex troubleshooting chart: http://xemodex.com/us/knowledgebase/dim ... low-chart/ You can try to walk it through, call xemodex and describe what you have.

[shiloh51933]

Some high-speed CAN bus module failed. Often it is CEM. Find a good car electrician.

Thanks for the response, vtl.
So, this would be an automotive electrician above and beyond the Volvo diagnostician/mechanic?
I just got off the phone with the Volvo mechanic he said there are no codes miraculously showing after a test drive. However, this happened to me a few times too, only to be left stranded when the vehicle decided to cough up some codes and die. Is that typical failure behavior for a CEM?
Go Pats - I hail from Maine!

There should be at least one diagnostic tech at every Volvo Dealership who was trained to diagnose an issue like yours with a hard book laptop with Volvo software. I would say that's your best bet unless you find an A tech who is a Volvo enthusiast. The Dealership can do it but it's gonna cost.
Is everything on dash going off then it's going into limp mode when this happens?

[Madijain-]

Hey JRL, Mike and shiloh51933, thanks for jumping in.
Here's the update... Dealership releases vehicle unharmed.
First, let me say, XemodeX is an amazing company. I have received an endless amount of help and patience from everyone I've spoken with. XemodeX took care of both the BCM and CEM with a 5 day turn around on each, from Germany to Canada and back, amazing! Brilliant customer service and a personal savings of roughly Nine Hundred Dollars!!!!
Secondly, with the help from this site and XemodeX, I learned a great deal and I was able to present myself as a somewhat knowledgeable person, to the mechanic, without being thought a fool and earning a trip to the cleaners.
Apparently, the BCM replacement allowed the vehicle to start consistently. (?) The new codes generated after the BCM install were caused by a faulty CEM. Y'all called it! After the CEM replacement all codes cleared. However, on test drive a tail gate open dash message appeared. The Volvo mechanic said he didn't find anything that could account for that message and I should come get the vehicle. I picked up the vehicle and within twenty miles Anti Skid Service and Low Tire Pressure messages appeared. I inflated tires to normal pressure and both new warnings messages went off. I also hooked up my OBDII to confirm that there are no codes present. All is well in the Kingdom!! Now just the pesky tail gate open, when it clearly is not, warning.
Thanks so much for sharing the wealth of information.

[precopster]

Does the tailgate open message coincide with the cargo light coming on? Also if you open the tailgate does the light in cargo bay work?

The rear module (yes another one) is reaponsible for rear cargo and door functions.

If you peel back the driver's side lining cover benearh the cargo window (a clip will release it) you'll see the module and it looks like rows of fuses and relays. Make sure they're all tight and contacting.

[JRL]

Probably a bad lock, they do go bad