Low Engine Oil Level Indicator

[Fierce]

Hi, 

i am new on the forum. i'm hoping to get some help/guidance with a challenge with my ES350 2008 model year. 

3 weeks ago , my car suddenly came up with this 'fault message' on its dash - 'Low Engine Oil Level Indicator '..

i had done an Oil replacement in April. i also checked my oil level as soon as I saw this , and the Oil level is okay - well gauged. I've checked every other day just to make double sure and its always gauged and on the right level. The alarm/notice clears after a few minutes of driving, But  continues to come and go every other day until the last 4 days where it seems to have worsened and become pretty regular/ more frequent. Today i've noticed that the light and fault message has been steady. It hasn't cleared for a minute. My Oil level is still okay, not short at all. 

Has anyone experienced this? Any idea of what this could be and how it can be resolved? 

Thanks in advance for your feedback.