Ulysse EODB warning light

Hi folks, I'm new round these parts
I have a 2001 (old style) Ulysse, and the EODB warning light came on the other day... took it into Fiat garage, they put it on their magic machine, and it showed no problems (that's £58 of no problems, inc VAT).
For another £110, they will spend 2 hours investigating further...
A while back the milometer (odometer) also stopped working, so (in my ignorance of all things mechanical) I'm thinking.... wiring.... but the garage said that if they find they need to replace the odometer, that will be a princely £600+
Anyone had this prob? Does no problems actually mean no problems, in your experience?
Advice and comments welcome... mille grazie

hi have this problem sometimes on my old 1997 2.0 petrol. speedo was tempermental ,management light on and off etc. after cleaning the sensor located underneath no difference,but eventually traced it back to the connector into the ecu . give the connectors a good clean.maybe it will do the job.