H II literally joined the LOC about 5 minutes ago, so am delighted to be giving my First offer of a solution so soon!
Whilst I have only just joined, we have had the RX300 for about 4 years, so it's a known entity.
Having had this problem a couple of years ago - a great deal of research on the. American forums lead me to a very simple fix - but it actually works!
More often than not the problem is simply that the fuel filler cap is not seated or tightened sufficiently or the plasticky rubber seal just inside the cap is worn or kinked.
I had not given this another thought, it having worked perfectly, since, until yesterday, whilst on a 200 mile round trip (I work in the NHS so essential travel!) but on the return leg, the VSC and EML lights came on - all else perfect no change in fuel consumption or performance - so eventually pulled over, undid the fuel cap 'massaged'.the seal a bit and refitted - ensuring I tightened it until the clicks started. Within a mile - all warning lights extinguished.
I am sure this solution has been posted a thousand times but hopefully it will be of help to someone.
Best
Simon
