This fault code occurs when the oil level sensor detects a high degree of pullution in the engine oil. e.g diesel, ad blue etc. On cars driving short distances this is a common problem.
If the car e.g is used for short distances and the car is stopped during the particle filter regenerating itself - the fuel added to the particle filter will eventually reach the engine oil - hence the problem. It doesn't necessarily mean that there is an issue with the vehicle.