I would have to know a bit more about your testing technique, but if you are interested in some reading material you might check these:

http://www.continentalimports.com/ser_ic030538.html

http://www.mercedestechstore.com/pdfs/507%20Systems%20I/507%20HO%20CAN%20B%20(ICC)%2010-28-02.pdf

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician