Bruce,

I just looked in my MB DTC Reference Guide and code 15 is indeed not used. I am inclined to agree with the previous poster that maybe the led blinking was miscounted and code 16 is the EGR. My 190E2.6 (103 motor & 130,000 mi) will sometimes set a 16 and 11 (air pump). Although I do not have a CE light, I pull codes every so often to see how the car is doing.

Rod