Abarth 500 showing oil pressure switch fault. Replaced part with new one from fiat but still same problem with triangle warning light on dash.

Anybody experienced this before.

That P code tells me you haven’t used MES to diagnose. That’s more likely to tell you whst the actual problem is.

Is that the generic yellow triangle with the exclamation symbol? Stupid question check your lights especially the day running lights.
If not measure the actual pressure with a gauge, the switch is either open or closed try earthing the switch see if the light goes out?