Why is my fiat puntos oil warning light on?

think I would start by replacing the oil pressure switch. On the FIRE engine (999cc/1108cc), it's mounted on the oil filter

mounting. Easy to get to but when you undo it, oil will drain out, so have a drain pan ready.

The switch is cheap and hopefully easy to get.

If the flashing light persists with a new switch, change the oil and filter

If the flashing light still continues, you will have to investigate further by taking the sump off (assuming a FIRE engine, the exhaust must come off first), and then remove the oil pump (for the FIRE engine, it unbolts from the front of the cylinder block once you remove the cambelt and pulley). On the back of the oil pump is a plate held on by countersunk screws. Those screws can work loose, causing oil pressure to leak away. It's an easy fix, but a fair amount of dismantling (and re-mantling) to repair.

WOULD ALSO CHECK CYLINDER HEAD OR ROCKER COVER FOR LEAKS AS THIS MAYBE CAUSING LOW PRESSURE