Oil light on

Hi everyone I am quite new to the site and in fact only a skoda owner for a year. Mine is a Fabia 1.6 tdi the problem is constant oil light on checked pressure ok level ok changed oil and filter. Had it plugged into vag gadget no fault shows. The engine runs great no knocks bangs as I said checked oil pressure has new switch. But the light does not want to go out.

Yours AAT frustrated ex mechanic from the pre electronic days of diesels.