Hi Kev,
I have a 2000 vito 108 CDI with EXACTLY the same problem. I've been stuck in limp mode for ages now and its driving me crazy....if anyone hears of a solution please help!! Took it to a Mercedes service centre and their laptop couldn't communicate with my ECU - all they told me was i had a rare model..... very helpful.
I've heard lots of different reasons for the EDC warning light to be triggered but none that seem to explain my problem. Any advice much appreciated
Dave