ECM 9400 error code from Vadis
ECM-9400 code points to the Brake Pedal Position Sensor which delivers faulty signal. It has

a bad engineering design similar to that of ETM. Regarding ETM failure, Don Willson has a detailed discussion at http://www.volvoxc.com/forums/showthread.php?t=6026
There is also newspaper article to detail the possible recall for ETM (http://www.detnews.com/2005/autosinsider/0505/03/1auto-170127.htm)

The following pictures shows the cause of Brake Pedal Position Sensor
failure. The sensor is a potentiometer resistance element. It has a wiper to wear a painted

resistance stripe. There will be million times movement for the wiper on this strip and it

will cause potentiometer to fail.
Pictures:
http://www.geocities.com/achvia/IMG_2412a.JPG
http://www.geocities.com/achvia/IMG_2415a.JPG
http://www.geocities.com/achvia/IMG_2418a.JPG

The sensor parts# is 9441116 and dealer charges $88 for it and 0.2 hour labor to install it.
This could be a potential recall too. It belongs to ABS control system as some one pointed

out. refer http://au.geocities.com/ozbrick850/abs-141142.html
I had this sensor failure starting from 43K miles and 5 year. The engine light went on and

off for period of time. The message board said "Engine System Service Required". I think the

message really did not tell me anything about the problem. The vadis later show the error

code. Since I fixed the sensor, I never see this problem again.
If you have same problem in your car, I can help you to fix the sensor. Contact me at

achvia@hotmail.com