Code P0521 help!!!

[mkoz]

Hi,
My '09 G8 GT has been to the dealer 5 times now for this 'low oil pressure' code. They've replaced the oil pressure sensor, the lifter filter, the oil pan relief valve, the oil pan itself (original leaked) and most recently the PCM (due to "internal failure"). I'm waiting for confirmation that their last diagnostic included checking the pressure with a manual guage. Can anyone think of anything else that could be causing this code? I know if the pressure really is low it could be the pump or pickup o-ring, but the engine sounds normal, so I suspect actual pressure is fine. Code seems to set most frequently when cruising at 55km/h with AFM engaged. Car is bone stock and otherwise behaving normally, just under 50K km on the clock.

Help!

[Crazy Paul]

P0521 is all about indicated oil pressure readings being way out of whack. Obviously you can't actually have 127psi or 1.16psi at the revs quoted below.

There's an electrical issue with voltages or the oil pressure sensor is fucked.


P0521
• The engine oil pressure is greater than 880 kPa (127.6 psi) and the engine speed is less than 640 RPM.
• The engine oil pressure is less than 8 kPa (1.16 psi) with the engine speed greater than 1520 RPM, engine oil temperature is between 80°C (176°F) and 110°C (230°F).
• The above condition is present is present for greater than 4 seconds.

See this thread: http://forum.grrrr8.net/showthread.php?t=29660

*** Replacing the Oil Pressure Sensor again with another new one is the next logical step.
Yes they do arrive faulty straight out of the box.

[mkoz]

See this thread: http://forum.grrrr8.net/showthread.php?t=29660

*** Replacing the Oil Pressure Sensor again with another new one is the next logical step.
Yes they do arrive faulty straight out of the box.

Thanks. I told them to order another sensor. It's going back in on Monday.

[GM Customer Service]

Hi,
My '09 G8 GT has been to the dealer 5 times now for this 'low oil pressure' code. They've replaced the oil pressure sensor, the lifter filter, the oil pan relief valve, the oil pan itself (original leaked) and most recently the PCM (due to "internal failure"). I'm waiting for confirmation that their last diagnostic included checking the pressure with a manual guage. Can anyone think of anything else that could be causing this code? I know if the pressure really is low it could be the pump or pickup o-ring, but the engine sounds normal, so I suspect actual pressure is fine. Code seems to set most frequently when cruising at 55km/h with AFM engaged. Car is bone stock and otherwise behaving normally, just under 50K km on the clock.

Help!

Mkoz,

I apologize for the concerns that you are having. What I would like to do for you is set up a Service Request number to document your concerns.. Please send me first and last name, address, phone number, VIN, current mileage and dealership.

Look forward to your reply!

Tina
GM Customer Service

[mkoz]

Mkoz,

I apologize for the concerns that you are having. What I would like to do for you is set up a Service Request number to document your concerns.. Please send me first and last name, address, phone number, VIN, current mileage and dealership.

Look forward to your reply!

Tina
GM Customer Service

Hi Tina,
Info sent via PM.

Thanks!

[mkoz]

See this thread: http://forum.grrrr8.net/showthread.php?t=29660

*** Replacing the Oil Pressure Sensor again with another new one is the next logical step.
Yes they do arrive faulty straight out of the box.

Oil pressure sensor got replaced for the second time today, unfortunately the code is back

[GRRRR8]

They need to hook up a mechanical oil pressure gauge and test it hot and cold. They really need to do it, not just say they did.

[Steve]

Perhaps your bypass valve in the pan in stuck open..
Of course I had the code too a few years ago after doing a stroker kit but my problem was I spun some cam bearings XD

[mkoz]

Perhaps your bypass valve in the pan in stuck open..
Of course I had the code too a few years ago after doing a stroker kit but my problem was I spun some cam bearings XD

The bypass valve has been replaced. That's not to say that it isn't sticking again. I'm trying to get my hands on software that will allow me to datalog extended GM PIDs so I can graph the oil pressure sensor data against PCM and battery voltage. I want to see if there is any correlation or erratic readings. The conditions for setting the code are almost always the same: cruise under light load 50-60km/h with AFM enabled. Today it happen while rolling in traffic on the way home. I have another dealer visit booked for next week and they want to engage the engineering group which leads me to believe they've done everything they said they did, including putting a manual guage on it.

[The Beej]

Mkoz,
My bet would be the oil pump. My dealer did everything including putting a manual pressure gauge to it, new pressure sensor etc. the light still came on. New pump problem fixed. Also even if you datalog, your still only going to see the psi the sensor sends to the computer not real time actual pressure, hence the suggestion for a direct pressure gauge.

Brandon