Momentary low oil pressure light when starting cold.

Hello Prius Hive,

I gave my 2010 Prius to my daughter 2 years ago. The other day I needed to move it and about 5 seconds after the engine came on, there was a short beep and the Low Oil Pressure on the display for 1-2 seconds and then it disappeared. I checked the car again the next day and same thing.

98,000 miles. Full oil. If the engine is warm, this does not happen. Oil service done by local, non dealer shop. Because so many people are wary of their car getting the correct oil, I did an oil change today. (I don't normally do it because my only access to the underside of the car is with a pair of jackstands and it's a pain.) After replacing oil and filter, it did it again, but that could have been due to the filter filling. It may be too warm for me to replicate with a cold engine until tomorrow morning.

If it isn't due to low oil volume or incorrect viscosity, and it only happens when cold, what else could it be? The Toyota parts image looks like it is shaft driven, not an electric pump like the water pump.
2010 toyota Prius Engine Oil Pump. Pressure - 1510037040 - Genuine toyota Part


But why would it only be trouble in that brief moment?

Thanks for your thoughts!

 

Everything is dry and clean, including the plastic access panel door. Prior to today, the last oil change was about 2000 miles ago.

 

Yes. I read several posts on the issue and so twice checked the oil level with a cold engine. It was basically up to the top marker on the dipstick.