Radiator cooling fan

[Jd4467]

Hello my engine radiator fan is constantly on and even stays on when ignition turned off and key removed. Even when car locked for up to 15 minutes. I have no idea why. Engine temp is ok. Thermostat recently changed. Ambient air temp sensor shows incorrect temperature intermittently

[PaulC5]

If the fan eventually goes off it might be the dpf was being regenerated. If it starts up as soon as the engine is started then it will be something else.