If a vehicle is driven on extremely short trips most of the time (where the engine never reaches normal operating temperature), the engine oil may become diluted with fuel and the engine oil level will increase. Engine oil dilution with fuel occurring under this specific driving condition is normal with direct injection engines. If the vehicle is driven on a longer trip after a lot of short trips (where the engine reaches normal operating temperature), the Check Engine Light may turn ON with DTC P0172:00 (Fuel system too rich).
