Only owned my 2004 XC70 for a few months now, and had the first opportunity to drive it in the snow... and it did HORRIBLE.

I realized that the rear wheels were not engadged, so I took it to my shop.

No check-engine light, no problem shown on the info display.

Found the following trouble codes:
Engine Control:
ECM5200 - Engine speed fauly signal
ECM6806 - Turbo Charger Control Valve, Flow fault, pressure too low
ECM9400 - Break Pedal sensor signal too high
ECM4801 - Three way catalytic converter efficienct intermittent faulty

Trans. Control:
TCMB003 - Configuration Faulty

Central Control:
CEM1A64 - COMM. With aoc (?) control modul signal missing - permanent fault
CEME000 - Control Module COMM Faulty Communications

Brake Control:
BCM0103 - Break pedal position sensor
BCME000 - Control module communications
BCM0041 - Wheel sensor right rear
BCM0031 - Wheel sensor left rear
BCM0011 - Wheel sensor left front

So, they reset the codes, and the AWD started working. They drove it around the block. All the trouble codes returned.

They're sending me to the dealership for a reflash/reprogram.

So, here are my questions:

1. What do you think the problem is?
2. How do you think it can/should be fixed?
3. What do you think this will/should cost?

Looking forward to hearing your thoughts. Thanks in advance!

- JB

 

bumpity bump bump, bumpity bump bump,

Look at Frosty go....

 

Hi,

I have a 2004 XC70 also and my rear wheels do not engage either. I wonder if you were able to find a solution to your problem. We don't usually get much snow in central Virginia but we sure have some now. Thanks for any help.

Jonathan Diveley

 

It's been a long and painful journey, but I'll give you the short answer. Dealer says it's a bad DEM (differential electronic module). They wanted $1800 for the part, plus labor, plus an extra charge for the "program" that they have to load onto it. About $2400 out the door. I tried to replace with two used DEMs from Erie Vo-Vo (best online resource for used Volvo parts with lifetime guarantee), but no luck. They wouldn't take the appropriate download at the dealership and communicate with the other systems. Finally had to man-up and order a new one. Best price I found was from a Volvo dealership out of California that hosts the website myvolvopartsonline.com - it was about $1200 shipped. Scheduled to be installed and programmed on Monday, Feb7th. Yes - that's how long I've been working on this. What a miserable deal. If you don't see any other posts from me, that resolved the issue! Otherwise, I'll be back with more sob stories... Hope this helps a bit!