Pegged engine oil gauge

[Trackman]

My 2004 Tahoe has been a faithful servant since I bought it new in'04. Oil change every 4K miles, not a hint of oil consumption or trouble. Yesterday I had a few new engine oil drops on the garage floor. Never has leaked prior. Wiped them up took a test drive and noticed my oil pressure gauge was pegged at 80lbs. No more leaks however gauge stays pegged ?

Ideas/comments?
Thks
The Trackman

 

[justirv]

My 2004 Tahoe has been a faithful servant since I bought it new in'04. Oil change every 4K miles, not a hint of oil consumption or trouble. Yesterday I had a few new engine oil drops on the garage floor. Never has leaked prior. Wiped them up took a test drive and noticed my oil pressure gauge was pegged at 80lbs. No more leaks however gauge stays pegged ?

Ideas/comments?
Thks
The Trackman

Not sure on pressure gauge pegged, my first thought is faulty sensor or perhaps internal debris (?). On the oil drip/leak, check the "oil cooler" block-off plate, they are notorious for warping, next to the oil filter on the side of the block.

 

[Trackman]

Not sure on pressure gauge pegged, my first thought is faulty sensor or perhaps internal debris (?). On the oil drip/leak, check the "oil cooler" block-off plate, they are notorious for warping, next to the oil filter on the side of the block.

Thanks for your reply - yes my shop says they replace those oil pressure sensors often. Scheduled into shop this week, will look for leaks in the area you mention.

 

[Fless]

Turn the key to "run" without starting it, and see what the oil pressure gauge reads. If more than zero, suspect the sender or its circuit, or less likely the gauge's stepper motor (in the cluster).

 

[InterceptorF]

You may have a bad cluster/oil gauge. If you take the gauge cluster out ( not very hard to do) there is a little white POS "reciever" ( the gauge itself) soldered to the circuit card. You can get them on Amazon or Ebay for cheap ~ $5.00. There are four solder joints to unsolder and it pops off the circuit card. I've had the same issue with my 2004 Pontiac Montana - speedometer, my 1997 Chevy S10 - temp, my 2003 Tahoe - oil and my 2001 Yukon XL - oil. TOnce its replaced you'll need to "adjust" the needle position. I have a mechanical aftermarket gauge I use connected to to the driver side bolt in the block near the front that I tapped on the YukonXL to verify the correct pressure and then set the cluster gauge needle depending on what it showed. On my 2001 YukonXL, I installed a Melling high output oil pump and when I verified the oil pressure. I was at 45 PSI cold where the cluster gauge was saying pegged; or you can order the whole cluster for ~ $250.00 and hope that fixes it. Also if ALL the gauges start fluxuating like crazy, there is the block ground behind the intake by the sending unit that is probablt not connected or is loose. Ive had that happen as well.

 

[jfoj]

@Trackman

Not sure if you have this issue resolved yet.

If you have a 6.2l engine, it has a 2 Stage oil pump with an electrically controlled solenoid that will trigger the oil pump to increase to around 80 PSI. I think the default state if the wiring gets knocked off or has a bad connection is for the oil pressure to go high.

As I recall the solenoid is not sold separately, it is part of the oil pump assembly, unclear if you could unscrew the solenoid and swap it, otherwise oil pump replacement is a rather involved job.

If you have a 5.3l, I believe since 2021? they did away with the 2 stage oil pump on the L84 engine.

A higher end scan tool can also read the oil pressure from the data buss to determine if the problem is the dash display, but I assume with a 2024 Tahoe the dash is electronic rather than an older analog motor driven gauge?

 

[Fless]

@Trackman

Not sure if you have this issue resolved yet.

If you have a 6.2l engine, it has a 2 Stage oil pump with an electrically controlled solenoid that will trigger the oil pump to increase to around 80 PSI. I think the default state if the wiring gets knocked off or has a bad connection is for the oil pressure to go high.

As I recall the solenoid is not sold separately, it is part of the oil pump assembly, unclear if you could unscrew the solenoid and swap it, otherwise oil pump replacement is a rather involved job.

If you have a 5.3l, I believe since 2021? they did away with the 2 stage oil pump on the L84 engine.

A higher end scan tool can also read the oil pressure from the data buss to determine if the problem is the dash display, but I assume with a 2024 Tahoe the dash is electronic rather than an older analog motor driven gauge?

He has a 2004. None of this applies. And he hasn't been on since the end of March.

As to the scan tool, the NBS years don't have a PID for reading oil pressure in PSI. There is one, however, for sensor voltage.

 

[jfoj]

My bad, That's what happens when you wake up at 4:00 in the morning I guess!

 

[S33k3r]

My bad, That's what happens when you wake up at 4:00 in the morning I guess!

Sounds like you weren't really awake...

When I first saw the title, my immediate thought was, "How does he know it's male?" My next thought was, "Yeah... I really don't want to know."

 

[PNWYukon]

Oil Pressure Sensor. Not exactly easy to get at.

 

[DoubleDingo]

Turn the key to "run" without starting it, and see what the oil pressure gauge reads. If more than zero, suspect the sender or its circuit, or less likely the gauge's stepper motor (in the cluster).

I did a search and this thread was the closest to what I am experiencing with my 2005 Tahoe LT 5.3. Was hoping @Trackman had posted the results of the fix. @Fless When I turn the key, my gauge pegs at 80. The gauge moves freely. I watched a video yesterday in the GMT900 area, the video was for a GMT800 and the sending unit connector wire somehow came loose. The guy making the video was using a scanner with a big screen, and it showed the oil pressure with the engine off and when it was on.

I have a Bosch OBDI/OBDII scanner that shows what the various sensors are doing. I hooked it up last night after work, but I didn't see anything on the scanner screen that showed oil pressure sensor, or oil pressure. There are no codes, and everything seems to be operating like it should, just have a pegged oil pressure gauge.

I guess I need to break out the multimeter and diagnose the connections to see what is going on back there. Any advice on what to check, what to look for, where everything is, and location of a wiring diagram to make it easier to follow along in the big spaghetti bowl of wires?

 

[Doubeleive]

I did a search and this thread was the closest to what I am experiencing with my 2005 Tahoe LT 5.3. Was hoping @Trackman had posted the results of the fix. @Fless When I turn the key, my gauge pegs at 80. The gauge moves freely. I watched a video yesterday in the GMT900 area, the video was for a GMT800 and the sending unit connector wire somehow came loose. The guy making the video was using a scanner with a big screen, and it showed the oil pressure with the engine off and when it was on.

I have a Bosch OBDI/OBDII scanner that shows what the various sensors are doing. I hooked it up last night after work, but I didn't see anything on the scanner screen that showed oil pressure sensor, or oil pressure. There are no codes, and everything seems to be operating like it should, just have a pegged oil pressure gauge.

I guess I need to break out the multimeter and diagnose the connections to see what is going on back there. Any advice on what to check, what to look for, where everything is, and location of a wiring diagram to make it easier to follow along in the big spaghetti bowl of wires?

just buy a oil pressure sensor, the oil pressure sensor socket tool. R&R and go about your day. On the gmt800's it's a breeze to do
you need the socket tool because nothing else fits, the tool is thin wall, then you just need a pick tool to get the harness off.

 

[Fless]

There's no PID to view oil pressure in the GMT800s, but there should be a voltage PID. See the thread below for the comparison if you want to try it with your scanner.

2004 K2500HD 6.0 oil pressure gauge problems

I have been seeing the odd oil pressure gauge reading for a couple days. Was completely normal. I think the problem is a stepper motor. If it is, I will just get a new cluster from Digital dash solutions. I have a Foxwell NT710 scanner that will graph oil pressure readings. The graph is from 0...

www.tahoeyukonforum.com

Otherwise buy the new sensor and plug it in without actually installing it. Turn the key on to see if the gauge pressure stays at zero. If so, install the new sensor with the correct sensor socket and be on your way.

 

[Doubeleive]

There is a slim chance the cluster gauge is fubar but way less likely
I would assume if you just reached in there with a pick tool and pulled the harness off it should just read 0
if the cluster passes a sweep test then you can put money on it being the sensor

 

[DoubleDingo]

There is a slim chance the cluster gauge is fubar but way less likely
I would assume if you just reached in there with a pick tool and pulled the harness off it should just read 0
if the cluster passes a sweep test then you can put money on it being the sensor

It definitely sweeps when the key is turned on or off. Off=zero. On=80, no bounce, no change when the engine starts. Turn off the key and back to zero, on back to 80.

 

[DoubleDingo]

Did a quick search on changing the sensor, and this was the first video I watched, this gauge in the video is basically what mine is doing. And now that I have watched this video, he says these sensors are notorious for leaking, I wonder if that is the oil smell I've been smelling. I bet it is, since I cannot find any leaks anywhere(I have not looked back there because I never thought I needed to). I'll be investigating this today after work. Looks like I'll be swapping vehicles at lunch so the 5.3 will cold when I work on it tonight.

https://youtu.be/f6GXwTgRKq0?si=SaWuwY5V6BlcF2bV

 

[PNWYukon]

@DoubleDingo How did it go? Get comfortable with the process and be prepared for your new "GM" sensor to fail. My 2004 sensor lasted 21 years. The new GM sensor failed in 4 months, then another a few months after that. I'll tell you that removing the intake manifold makes this job super easy!

 

[Doubeleive]

@DoubleDingo How did it go? Get comfortable with the process and be prepared for your new "GM" sensor to fail. My 2004 sensor lasted 21 years. The new GM sensor failed in 4 months, then another a few months after that. I'll tell you that removing the intake manifold makes this job super easy!

absolutely no need to remove the intake, this is a 5 minute job on a gmt800

 

[Fless]

absolutely no need to remove the intake, this is a 5 minute job on a gmt800

^^^ This. Yes, most of it is done by "feel" but is not very difficult. I placed a board and a pad across the engine bay to give me a place to lie on top of the engine to replace the sender. Use the correct sender socket or you may find it difficult.

 

[Doubeleive]

^^^ This. Yes, most of it is done by "feel" but is not very difficult. I placed a board and a pad across the engine bay to give me a place to lie on top of the engine to replace the sender. Use the correct sender socket or you may find it difficult.

height may certainly play a factor, I am 6'4 so all I needed was a pick tool, flashlight, the sensor socket (thin wall) and a ratchet & short extension.
used the flashlight to see the harness clip orientation, used the pick tool to release the harness, used the socket to r&r, then looked again with the flashllight to see harness orientation and replace harness.
the only other thing to do is remove the single bolt engine beauty cover.
it's literally that easy