how does it know

[Gareth45]

How does the vehicle know that the engine oil has been replaced.I have been told if you change the engine
Oil at any milage that the oil service light needs reseting is there a float switch any advice

 

[Jonesey]

I have not seen this here in the US - I've changed my oil twice and never had to reset anything.

 

[dad of jon]

you have it reset in the 'service' menu.

 

[nizzy1115]

My last mazda it was a dumb mileage counter. Had 1 for tire rotation and one for oil change. US cx5 does not have it.

 

[cwstnsko]

I believe the EVIC that comes with the Tech package in the US includes maintenance reminder mileage counters, and they would need to be reset. Without the tech package, there is nothing to be reset.

The OP's original question appears to be related to the diesel motor, so it may also be different than the simple counters in the tech package in the US.