VW golf mk4 engine light not working

[MrSkeedle]

my car has just failed its mot on a couple of things, one being the check engine light not working. very annoying! the car is fine but the light itself isnt coming on. I've had the dash apart and there is nothing covering the light and the LED looks fine. Is there anyway to test this? I've heard it could have been coded out to stop it coming on. maybe this is what one of the previous owners did to sell it??? so basically when I turn the ignition on, all the lights come on that are supposed to except the MIL light.

thanks in advance