Oil alarm

[steplift20]

I just came from my boat, checked the cap. Checked good
Replaced the oil motion sensor with a old one I kept that was good and alarm still sounded
I'm thinking the oil module? The only thing is it's expensive and I want to be sure,is there a way to check the module? If not then I'm hoping yo have to chance it
The only thing that might give you a clue I that when you turn the key it beeps three times like it should but as soon as it starts it beeps imidiately. No delay at all I hate to spend. All that money if I don't need it but if I need it then I would love to spend it. Thanks for any insight to this problem.