No oil pressure???

New Envoy

Original poster
Member
Oct 20, 2012
56
Hi everybody. I have an 06 Envoy Denali, with the 5.3. Everything works fine, no troubles at all. This morning the girlfriend was taking it to work and the low oil pressure light came on, and then the stop engine light. So, she drove it the short distance back home, said she heard no knocking or funny sounds. The oil is about 1/2 a quart low, no where enough to make that happen. Im thinking the the oil pressure sending unit/switch is going out. Any body have any other ideas? Or thoughts? By the way, it has 75,000 miles on it. Thanks everybody.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
In a V8, it's a sensor (I6 has an on/off switch), and yes, they fail. Rear of the top of the engine.

View attachment 25582
 

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New Envoy

Original poster
Member
Oct 20, 2012
56
Thanks Roadie! But it didnt help..... Now that im home and can look at it and hear it, The motor sounds fine, oil is full. But, now Im thinking the gauge itself might be bad? When I first start it up, it acts like the needle is going to go up to where it should. It moves just a hair, and just for a second, then nothing. I am thinking that I hear something as well. Sounds like a record scratch almost, and just does it for a second when I first start it up, and it sounds like its coming from behind the dash.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Oh, that's the gauge stepper motor. Usually it's the tach or speedometer that goes first. Confirm by getting a scangauge or good scan tool that can read your data stream for the oil pressure. Then buy six new steppers and solder them into your gauge cluster. There's an article here somewhere.
 

jimmyjam

Member
Nov 18, 2011
1,634
the fact that the dash read low pressure leads me to believe it is not the gauge.

*edit*
if you have a cheap odb2 bt adapter and torque, the pid for oil pressure works for the v8, you could verify there.
 

New Envoy

Original poster
Member
Oct 20, 2012
56
I actually own a GM TECH II!!! But, dont really know how to use it! I have another scan tool, but it wont show the oil pressure. I got the tech II to the part where it should show me the engine data. then it says something about CANdi not detected. Trying to figure that step out now.

And Jimmyjam, you lost me...

EDIT: I just got a code of P0522. Maybe a bad "new" sensor???

EDIT AGAIN: Just did some looking online and, I got the wrong switch!! They gave me one for the dash with a light. I have the actual gauge. SO, pulling it back out and going back to the store!
 

jimmyjam

Member
Nov 18, 2011
1,634
candi plugs in between the tech2 and the odb2 port

i was talking about the cheap "elm" bluetooth odb2 adapter, the sell on ebay for around $15 and you can use them with a cellphone running android and the free app named "torque"

New Envoy said:
I just got a code of P0522. Maybe a bad "new" sensor???
you changed the sensor already? maybe you didn't plug it in all the way?
 

New Envoy

Original poster
Member
Oct 20, 2012
56
OK, I got the first "new" sensor out, and there was oil on it.:wootwoot: So now I know that I have oil pressure. So, I took it back to the parts store, got the RIGHT sensor, installed it, and got the same thing, no pressure at the gauge. So, I sat there for a sec, thinking, and reved it up for a sec. BINGO, the gauge jumped right up, and the "check gauges light" went off. So, I cleared the code and closed the hood. Will drive it for a few days and see what happens.....
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
New Envoy said:
I actually own a GM TECH II!!! But, dont really know how to use it!
Have I got a deal for you. Box that sucker up and send it to me, and I'll WRITE you a manual how to use it with the vehicle. May only take me ....... about 4 years to complete, then I'll send it all back. OK? I'll pay postage!

Seriously, it has decent value if you ever want to sell.
 

New Envoy

Original poster
Member
Oct 20, 2012
56
Actually, I am thinking of selling it.... I know its a real useful tool. I also know its way more (whats the word Im looking for) detailed, than I need. And now, I find out I need that CANdi thing. That I know, Ill probaly never buy. I just hate to see it sit there unused going to waste. I guess I kinda look at it as a little old lady that buys a Porshe to go to the store once a week. Its just overkill for what I need.
 

New Envoy

Original poster
Member
Oct 20, 2012
56
She drove it to work this morning, no problems. She drove it home, and the check engine light came on. the oil pressure gauge seems to be working fine. I checked the codes, its a P0521, Engine Oil Pressure Sensor/Switch Circuit Range/Performance. So, now what? Any ideas? I did check the new sensor, it was a hair loose, maybe 1/4 turn. I also noticed that the rubber O ring from the connector is missing. You know how the NORMALLY stay on the connector, well this one didnt. I cant find it or the old sensor to see if its in it.

EDIT: OK, I found the original sensor, and it had the O ring in it! It also had a little plastic piece in it, kind of a wire retainer thing. I put it and the O ring in the new sensor, reinstalled the sensor, and cleared the code. I will report back with any new news. Hoping this fixes it.
 

New Envoy

Original poster
Member
Oct 20, 2012
56
Ok, put about 150 miles on the Envoy today, gauge works fine, no check engine light. So, in summary, it was a bad oil pressure sensor. BUT, just remember to put in the little plastic spacer thing and the rubber O ring. Thanks for all the help.
 

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