Engine /EML/ diesel particulate filter /DPF/ light on just check fault code if P252F fault is set only the problem is engine oil level is too high what is calculated by engine ECU NOT with engine oil level sensor is not fit in the engine so don’t start looking the location, check the engine oil level manually, if overload better to replace with oil filter. I see a couple of cars that it was overfilled with 6-7 litre fuel, so it needs attention. Recommend engine oil 5w30 C3 /C3/ protect the DPF system.
Why is the level growing up? The DPF is not regenerating properly for some reason and keeps spraying fuel in. When the DPF start regenerating it needs extra heat and the spray of some fuel helps the DPF. Normally the Mitshubishi technician after the service, resets the engine oil level calculation /is on the service list/ to 0 so if you run to the local garage is not sure if is done the reset.
How DPF work some info is here: Mitsubishi L200 DPF System How Is work?
A couple of things why not regenerate the DPF, driving condition is not met, is in the owner’s manual, the fuel level is too low recommend half tank fuel, any fault code is set, some DPF temp sensor is not working correctly and is have 3 in so check the data list have to be close all 3 sensors if 1 to far out is a fault, other main things the EGR valve not always get fault code has vacuum side and electric motor side check vacuum side manually and the data list any different between the ECU what tell and the real EGR movement.
How to reset the engine oil level? With MUT diagnostic machine go to engine -special function-initialisation-exchange engine oil level reset to 0 and is done.