Indications "Check System (Engine)" light on

Went out to use my car today and immediately on switch on I was confronted with the "Yellow" symbol, page 464 of manual.

The blurb says "Engine Emissions control systems may have a problem"

Car is just 3 weeks out of warranty.

So what have I done over the last 48 hours.

1. Let my pregnant wife drive as I was drunk, she jerked it about a bit in 1st at roundabouts.

2. Filled up 40 litres @ 11am on my last drive, Shell normal Unleaded, Hillington Glasgow.

Any advice on common issues associated with this, have restarted engine a few times over the last few hours, still the same.

** Unlike thread below there is no textual "Check System" message
http://www.civinfo.com/forum/engines...nt-sensor.html