Hi John can't seem to get the code up, erased the light last time car is running perfect that's why I changed the fuel cap but its come back on again, think my battery might be on its way out though its at least 5yr old if I don't use it for about 3 days vents don't open and get low battery message but the light originally came on after doing a 360 mile trip to Cornwall but it brought me back with no worries that's why I was thinking it was something simple ?