P0521 oil pressure code????
Thread Starter
Burning Brakes
Joined: Apr 2010
Posts: 1,001
Likes: 37
From: Farmington Missouri
P0521 oil pressure code????
Anyone have this come up? My car is apart for the winter, but a week ago I would get the P0521 code for oil pressure. The dash was showing 60psi, I would clear the code and would go to the normal 40 when cold and 34 hot. A few start ups later, and the code/high pressure readinf came back I put a new oil pressure sensor in, but still got the code and the high pressure reading. Clear and back to normal etc.
Team Owner
Joined: Jan 2007
Posts: 29,063
Likes: 1,839
From: cookeville tennessee
Dave do you think if it is truly going to 60 psi that is will hurt the car in some way. If you put in a new oil pressure unit & it still doing it I would think something may be going crazy with your oil pump in the car.
For the normal pressure in these c7 only read and seen around the 40 psi mine will run just under 40 to just over 40. This will be due to cold r hot temps of the motor. I would be worried by what you have said & done if the oil pump will be going out in the future. How many miles on the motor & who did the build if aftermarket motor in the car. Robert
For the normal pressure in these c7 only read and seen around the 40 psi mine will run just under 40 to just over 40. This will be due to cold r hot temps of the motor. I would be worried by what you have said & done if the oil pump will be going out in the future. How many miles on the motor & who did the build if aftermarket motor in the car. Robert
Thread Starter
Burning Brakes
Joined: Apr 2010
Posts: 1,001
Likes: 37
From: Farmington Missouri
I don't think it really has 60psi. If I clear the code while it's running it instantly drops back to 40. My current engine was built by Thompson Motorsports and has seen a lot over the past 2.5 years and survived several supporting part failures and is still going strong. I will probably pull it out for a refresh while the car is down and waiting on the glide.
Instructor
Joined: Oct 2018
Posts: 109
Likes: 43
Not telling you anything you probably don't already know...
just thinking out loud...
the oil pump is a variable speed and pressure pump. It has a feedback loop. It has a psi it tries to maintain at all times.
it also has a poppet valve if too much pressure is against it.
I bring all of this up because i believe it could be running 60psi... it has the potential to.
gm likely has more than 1 sensor measuring oil pressure... in case 1 goes bad.
my off the wall guess is that the oil pressure device/sensor that commands the feedback loop to the oil pump... that sensor is going bad or interference somehow... which commands the pump to pump harder by mistake.
then, another oil pressure sensor is picking up on the increased pressure, and throwing the code.
since this is all electronic....it COULD be that somehow clearing the code resets this scenario somehow.
then it begins to snowball again over time via the bad sensor.
I have no idea if I'm right, just a shot in the dark since no one else seems to have anything either
just thinking out loud...
the oil pump is a variable speed and pressure pump. It has a feedback loop. It has a psi it tries to maintain at all times.
it also has a poppet valve if too much pressure is against it.
I bring all of this up because i believe it could be running 60psi... it has the potential to.
gm likely has more than 1 sensor measuring oil pressure... in case 1 goes bad.
my off the wall guess is that the oil pressure device/sensor that commands the feedback loop to the oil pump... that sensor is going bad or interference somehow... which commands the pump to pump harder by mistake.
then, another oil pressure sensor is picking up on the increased pressure, and throwing the code.
since this is all electronic....it COULD be that somehow clearing the code resets this scenario somehow.
then it begins to snowball again over time via the bad sensor.
I have no idea if I'm right, just a shot in the dark since no one else seems to have anything either
I'm Batman..
Joined: Apr 2014
Posts: 6,142
Likes: 921
From: Lehigh Acres FL
Tech Contributor
Dave, I believe you can hook up a pressure tester to the top of the valley by the oil pressure sensor and see what you actually have vs what it shows on the dash. That will tell you if its a mechanical or electronic inconsistency..
Last edited by FYREANT; Nov 26, 2018 at 05:43 PM.
Le Mans Master
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From: League City Tx
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Le Mans Master
Joined: Mar 2010
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From: DFW TX
Good stuff right here! I had a similar issue the first time time I did a blower on my 14. Ended up being the sensor.... but mine didn't show any oil pressure at all. 
was a little scary cause the car had like 1000 miles on it in 2014.
was a little scary cause the car had like 1000 miles on it in 2014.
2nd Gear
Joined: Jun 2023
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