Hi, it refused to start 11pm, (going home time !), at work a couple of weeks ago, can hear petrol pump running / pressurising for a few seconds upon switching on ignition as per normal. CHK lamp flashing fast, continually, starter turns engine over normally but doesn't fire at all. Spark plug out, resting on cylinder head = very healthy spark.
Bought Chinese 7in1 DTC reader, when all connected up, it can't establish communication with ECU. So will soon be on the hunt for an affordable m/c DTC reader that works.
BTW, USB to UART driver correctly installed into laptop, software runs fine but only seems to support three SYM RV models. Spotted a proper SYM DTC reader on eBay but it's too expensive !