Modern Vespa

Hello all,
Need your advice related with oil pressure warning light on my Vespa gts 250. I've changed oil and oil filter. After warming up (drive) oil warning light goes on while on low rpm. With rpm going slightly higher it goes off. After switching Vespa off and start warning lights remain on (till moment I increase rpm). After cooling Vespa down (10 min) and starting again warning lights immediately goes off (as it should).
Any recommendations what could be an issue (pressure sensor, oil pump) ?
Thank you in advance for your response.

Was there a problem with the light before you changed the oil?

Yes. First I did was changing oil and filter but issue remains.

Do screw the dipstick in when checking the level?

Yes. Oil level is max

Hmmm. Maybe a low battery could interfere with the sensor? But I'm thinking it's the sensor failing?

Battery is 2 months old. I've ordered new sensor - hope that's the issue.

Sensor replaced - issue still in place. After warming up oil pressure lamp on while on low rpm? Any further suggestions ?

Maybe the regulator at low rpm is not supplying good voltage to the sensor?

Can also be that the oil pressure is too low, that's what this sensor is there for.

if it's like description say, oil lamp comes on when scooter is at idle and with warm oil, I think the issue is low oil pressure.

Cold oil get higher oil pressure than warm oil.

Do you have possible to measure oil pressure?

I would taken this warning light seriously, it's there for an reason

Battery replaced, sensor replaced, oil level at max, but the issue remains.

It is a bit strange you did experience the issue after an oil change.

You filled it with oil with the correct viscosity?

I had a similar issue with a car many years ago. Oil pressure light came on when the engine was at idle.
I do not want to worry you too much, but that happened to be a worn crankshaft bearing

They said the problem existed before the oil change so not overly surprised that it existed after.

OK, missed that.

Here's a new q

When changing the oil did you pull out the strainer from behind the plug and inspect + clean?

I bought Vespa with damaged crank shaft. I bought the new one and replaced it recently. will try to find the way to check oil pressure - thank you for showing expected values.
I'm thinking now about malfunctioning of oil pump. I checked it visually and seems to me that was working ok. That could also be a reason of crank shaft damage before.
Will come back to you with results.