Oil Lamp On, no error code

[KateKroger]

My 2007 Opel Movano has the oil light and stop light on. I have been to a garage who have changed the oil and filter, checked the oil pressure. They didnt have time to troubleshoot further but suggested the oil pressure sensor was duff. I changed this sensor however the light still is on!
The van drives fine and the oil level stays consistent. I have measured the oil level sensor and that has continuity across it, which suggests it is working. I'd rather not remove the whole oil pan but Im stuck at what to do next.
No error codes are coming up either.

Any ideas?