2008 Prius Oil Pressure Warning comes on and off

Your motor will quickly eat itself if the oil pressure is low. This is something that a dealer needs to look it. Are you sure you put a least 3 quarts of oil in?

 

Your engine's oil pressure apparently is low. This can cause permanent damage to the engine if allowed to continue.

1. Check the engine oil level when the car is level, and IG-OFF. It should be between the two dimples on the dipstick.

2. See if you can figure out exactly where the oil leak is coming from and if this provides a clue about the low oil pressure.

If 1 and 2 do not produce any insights, then I recommend that you immediately have your car towed to your local Toyota dealer for assistance. Perhaps the engine oil pump or the oil pressure sender unit has a problem.

I recommend strongly that you discontinue use of the car until this problem is figured out. Good luck.

 

What did you find to be causing the low pressure?

 

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That means it's definitely low oil pressure then. Make sure you don't drive the car like this, because it can seriously damage the engine very quickly.

BTW. Thanks for the update and please let us know how it turns out. I don't recall anyone else here having that particular problem, so it will be interesting to know what it turns out to be.

 

Arh, that's really significant information that puts a completely different slant on the problem! Since the engine doesn't even turn at speeds under 42MPH in EV mode, then yes that makes it much more likely to be some kind of electrical problem. Obviously when the engine isn't spinning then it wont produce any oil pressure (as the oil pump is still a regular mechanical type) so I'm guessing the software must disable the low oil pressure warning when the engine isn't spinning.

Now the other possibility is that it only happens in EV mode at 42 MPH and above (or below 42MPH in the case of stage 3a operation) , in which case the engine is normally turning at only something like idle speed. In this case it really could indicate a loss of oil pressure due to worn bearings.

So please see if you can determine if this happens in EV mode when the engine is turning or when the engine is off. This really makes a difference to the diagnosis.

 

BTW. Sorry about the jargon, stage 3a operation is where the Prius is running purely in EV mode but still the engine continues to run with fuel injection (very annoying I know but it's true, if you do a thread search you'll find lots of information these "stages" of hybrid operation). To detect this you'll need to either be really good at listening to the engine noise or else to have some way of detecting fuel injection.

If this does turn out to be the problem (low oil pressure at idle even after changing the oil pump and sender) then one way to confirm the problem is real is to try a heavier oil. You could even go as heavy as 15W40 to test this, assuming that the weather in Ark is fairly warm this time of year. (Yeah I know the 0W20 fan club are probably going to jump all over me now hehe , but I'm serious about this). If this test "corrects" the problem then you were genuinely getting low oil pressure at low engine RPM, and it may indicate worn bearings.

Obviously I'm assuming that you've already changed the oil filter with the oil.

 

Also, one more question jinkiesscoobygirl. What brand/grade oil are you currently using and have you mostly used in the past.

 

Take out the oil pressure switch and replace with an oil pressure gauge (from breakers if you do not have one) put car in maintenance mode and run engine till warm, oil pressure should be at idle above 4.2PSI at 2500RPM 22-80PSI. If pressure is low check oil pump release valve for sticking or for a weak or broken spring, after this if nothing is found I am afraid it will be bearings.

 

+1 regarding Britprius' suggestion.