2000 jetta v6 epc issue
 

a friends 2000 jetta has had the epc light come on recently with loss of all throttle response, it seems to come and go.it was scanned with the newest best snap on scan tool with no codes,is there a special vw tool that's required for this type of fault, what is the first thing he should check out? it seems this website has no breakdown for specific jetta years, is this the case?