Oil Pressure and CEL??

[The Beej]

I've got a 2009 G8 GT w/ 59k on the clock. I bought it used back in Oct. Last Friday the CEL lit up so I dropped it at the dealer(extended warranty) and they changed the Oil Pressure switch. I picked the car up Tues night and put about 20mi on it and CEL came back, so it went back to the dealer today.

Here is what I was told by the service advisor: The Oil Pressure sensor is tripping the CEL when it reads 29psi(caught it using a Tech 2) He asked if the car had an aftermarket tune which to my knowledge it doesn't as it's bone stock including paper filter. They have a call into GM Engineers to see what info they have.

I'm just curious as to what is happening with the car. From what I can gather factory oil pressure should be around 21-55+ depending on oil type, temp & driving conditions. If this is the case why would the CEL trip at 29psi??

Thanks,

Brandon

[-Ray-]

There is a procedure to follow when oil light comes on to diagnose. Hopefully they will take another path this time.
I don't have an answer to why it would come on at 29 psi, since that is a normal oil pressure at idle.

[todds87ss]

The oil pressure does not cause a CEL at pressures as low as 20 psi. Please post the code (have it scanned at AZ).

[The Beej]

I may pick it back up tonight and look at it myself and post here as well. I've always worked on my own cars but I bought and extended warranty with this car because I don't know the history on it. I'll get back to you guys...

Thanks!!
Brandon

[-Ray-]

Good luck brandon.

[The Beej]

Ok so just talked to the dealer again, they put a new ECM thinking that was the issue and it wasn't so now they want to put in a new oil pump..... Asked for the code and was told P0521, a quick search leads me to believe the little valve in the oil pan??

Thanks
Brandon

[-Ray-]

Here's a decription

[The Beej]

Thanks for the info Ray!! Should I let them continue or should I pick up the car? So far they have changed the Oil Pressure sensor, and ECM. Next step for them is changing the oil pump... Is that a logical step?

Thanks

[Crazy Paul]

Thanks for the info Ray!! Should I let them continue or should I pick up the car? So far they have changed the Oil Pressure sensor, and ECM. Next step for them is changing the oil pump... Is that a logical step?
Thanks

No.

I'll post the full DTC sheet in a minute. It tells you the course of action to take.
There's nothing there about ripping the engine apart or changing out ECM.

It wouldn't be the first time that a new oil pressure sender (like the one they just installed) was defective straight out of the box.

[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.

[Crazy Paul]

P0521 in full

http://www.grrrr8.net/crazypaul/P0521.pdf

[The Beej]

Thank you for all the info sir!!

[GRRRR8]

I would have the dealer manually test oil pressure with a gauge, not a scan tool. Steve went through this and once he had his motor replaced it was fixed. Keep in mind this was his 2ND engine. Anytime you think you might have a mechanical issue, do a mechanical test.

I have seen many defective sending units, but after helping Steve with his car and the dealer trying everything, the issue turned out to be a issue with the check valve in the oil pump sticking intermittently.

[The Beej]

I'll give the dealer a visit Monday morning as they are waiting on a oil pump. Try to get some more info from the advisor or tech that is working the issue. I appreciate the help and info!! I'll report back on Monday.

Thanks
Brandon

[Crazy Paul]

I'll give the dealer a visit Monday morning as they are waiting on a oil pump. Try to get some more info from the advisor or tech that is working the issue. I appreciate the help and info!! I'll report back on Monday.

Who's paying for the parts and time they keep throwing at this thing?

[todds87ss]

I have a rig to test this, if you find yourself down here (houston). Since it's at the dealer, I'd just encourage them to mechanically test it before continuing. Sounds like a pinched wire to me, though.

[The Beej]

My extended picked up the sensor and my factory power train or the extended is picking up the pump. However after the tips you guys have given I'm going to swing by first thing tomorrow and see if I can talk to the Tech. Btw just noticed this corner is for Non G8 related tech stuff, so I apologize for putting this in the wrong spot!

[todds87ss]

as long as the issue gets fixed, I don't think it matters where you post it.

[The Beej]

So I picked the car up on Monday and the service advisor swore to me it wouldn't hurt the car to drive it, and they had a new oil pump on order. After not hearing from them all week I decided to call and get an update on the parts. Said they were coming from MI and hoped to have them by Mon. Also told me that the reason the light is coming on is because the oil pressure will drop 1psi below the threshold and will at times stay above by 1-2psi. After driving it all week I was starting to think it was electrical because the light went out for a couple days and came back yesterday after work (raining here in Ft Worth.) So I have the car currently, I need to do some searching and find what’s need to test the oil pressure myself mechanically (pretty sure it’s on here somewhere) and see if I can't confirm what they are seeing with the Tech 2.

[-Ray-]

I'm too tired tonight, but one of us will come along and show you what you need to do to measure oil pressure with a pressure gauge.

[The Beej]

Yeah I hear you on the tiredness. Been a very long week, just found out that my unit is gonna be hit pretty hard by the new military downsizing plan, and I have a ton of homework to do this weekend.

Again I want to say thank you to those of you have helped me with this issue!!

Brandon

[Crazy Paul]

I'm too tired tonight, but one of us will come along and show you what you need to do to measure oil pressure with a pressure gauge.

There's a couple ways to do it.
The hardest part is getting the adapters.

Method1
Remove the blanking cover near the oil filter. Some oil may come out.
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/oil%20sender%20tee/08L76G8.jpg

Attach a threaded cover back on.
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/oil%20sender%20tee/Tee101.jpg
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/oil%20sender%20tee/Tee100.jpg

Adapt from the new threaded cover to a pressure gauge....via hose and fittings, or install an aftermarket sender in the side thread and run to a second electrical pressure gauge which is known to be accurate.. .



Method2
Remove the oil pressure sender from the rear of the valley cover. No oil will come out.
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/oil%20sender%20tee/L76-711.jpg

Install a Tee piece with a threaded outlet.
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/oil%20sender%20tee/P10104370-500.jpg
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/oil%20sender%20tee/R1010752-500.jpg

Re-install original GM oil pressure sender into the new Tee piece
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/oil%20sender%20tee/R1010747-500.jpg
http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/oil%20sender%20tee/R1010748-500.jpg


Adapt from the new threaded outlet to a pressure gauge....via hose and fittings, or install an aftermarket sender in the side thread and run to a second electrical pressure gauge which is known to be accurate..

[-Ray-]

Thanks Paul, I knew you would have stored pics.

[todds87ss]

the less expensive way is to use method 1, by a spare cover (GM 12577903), drill (11/32) and tap it to 1/8 npt, install a brass 1/8 npt to compression fitting (Lowes or HD), and run your gage.

[Crazy Paul]

the less expensive way is to use method 1, by a spare cover (GM 12577903), drill (11/32) and tap it to 1/8 npt, install a brass 1/8 npt to compression fitting (Lowes or HD), and run your gage.

Yeah true, not everyone has the equipment or skills to DIY the cover or is willing to get spilt oil at home.
More options are a good thing.

[The Beej]

You guys are awesome!! Route 1 will prob be the way I go when I get some free time on Monday. I have all the stuff here at the house to modify a spare cover plate aside from the fittings.

[pacmann]

Is there anywhere I could order the predrilled and tapped plate like the one in the pic Paul posted?

[Crazy Paul]

Is there anywhere I could order the predrilled and tapped plate like the one in the pic Paul posted?

Sure, they're on e-bay.
Search "CBM-10820"

The other swivel adapter for the rear of the valley cover is my own creation. I have them CNC machined from 316 stainless steel and always try to keep some in stock.

[black bart]

I would just like to say a very large thanks to Paul for his fantastic input on problems encountered on this site. I have worked on Chevy small blocks since 1955, but Paul's knowledge humbles me with each tech post. You are the man Paul!

[The Beej]

Thought I'd drop in and give an update. I went ahead and let the dealer change the oil pump, when talking to the lead tech he said he's seen it a couple times. I picked it up Thursday night and so far no light in about 150mi. This Fri I will prob order the atari gauges, as well as the fitting Crazy Paul posted so I can run a manual guage at times. I want to say thank you again for the responses in this thread!! Over on the C5 boards I would have prob got "Use the search" or scolded for posting in the wrong section.

Thank you to you all!!

Brandon

[-Ray-]

Glad it all worked out for you.


Sent from my iPhone using Tapatalk

[Torqued]

What is pn for the engine oil pressure sensor? I'm getting the P0521 and P0523 codes.

Thanks

[Crazy Paul]

What is pn for the engine oil pressure sensor? I'm getting the P0521 and P0523 codes.
Thanks

V8 up to MY09.5 12616646

V8 from MY09.5 12621234

[Torqued]

Thanks Paul.