More Oil Pressure Wackiness

[Clack]

I started getting the bad sensor/sender CEL last May. Changed it out, no problems until March of this year.

Again, P0521, but this time the gauge is bouncing between 0 and 40. With the oil supply o-ring advice being a more difficult repair on 4WD, I decided to replace the sender/sensor and screen again. All good until Friday.

Come this last Friday, it just reads 0 with the check engine light on. Never gets hot. I believe oil pressure is fine. Just doesn't display as such.

This time the code is P0523. If I clear it the gauge pegs out at 80. Then I get the CEL again and it goes to 0.

I read somewhere in here this is a ground issue. Where is the other end of this sensor line? Anyone else have any ideas?

Thank you,
Brian

 

[NickTransmissions]

I started getting the bad sensor/sender CEL last May. Changed it out, no problems until March of this year.

Again, P0521, but this time the gauge is bouncing between 0 and 40. With the oil supply o-ring advice being a more difficult repair on 4WD, I decided to replace the sender/sensor and screen again. All good until Friday.

Come this last Friday, it just reads 0 with the check engine light on. Never gets hot. I believe oil pressure is fine. Just doesn't display as such.

This time the code is P0523. If I clear it the gauge pegs out at 80. Then I get the CEL again and it goes to 0.

I read somewhere in here this is a ground issue. Where is the other end of this sensor line? Anyone else have any ideas?

Thank you,
Brian

Check continuity at the pigtail for the sending unit to confirm it’s receiving it’s required voltage to rule in or out a ground issue. Our trucks are known for bad grounds across multiple years/vintages so wouldn’t be surprised if that’s the problem.

If the dash gauge is pegged to max, it’s usually a sign of a bad sending unit.

Did you replace the sending unit with an OEM unit?

Id also remove the sending unit and screw in a mechanical oil pressure gauge, fire it up and take a reading, just for piece of mind’s sake.

 

[swathdiver]

I started getting the bad sensor/sender CEL last May. Changed it out, no problems until March of this year.

Again, P0521, but this time the gauge is bouncing between 0 and 40. With the oil supply o-ring advice being a more difficult repair on 4WD, I decided to replace the sender/sensor and screen again. All good until Friday.

Come this last Friday, it just reads 0 with the check engine light on. Never gets hot. I believe oil pressure is fine. Just doesn't display as such.

This time the code is P0523. If I clear it the gauge pegs out at 80. Then I get the CEL again and it goes to 0.

I read somewhere in here this is a ground issue. Where is the other end of this sensor line? Anyone else have any ideas?

Thank you,
Brian

Like Nick said, did you use a GM part?

If the part if working, the wiring is working the troubleshooting guide leaves one other possibility, your ECM might need replacing.

AllDataDIY

 

[mikez71]

Could the sender be dying/dead? My pressure reads 2psi with engine off..

 

[j91z28d1]

my oem one failed maxed out like that.

my replacement that I thought was oem off Amazon failed a few months later by flickering some at the end of long drives, like over an hour. it did get worse and happen sooner over the next few weeks. so before a long distance tow, I got a new one from a local dealer and it's been good so far.

 

[Clack]

Both OEM correct parts. No reason to believe they were not genuine. https://www.amazon.com/dp/B01FRENAA0?psc=1&ref=ppx_yo2ov_dt_b_product_details

I'm no good on electrical stuff. Wouldn't know how to check continuity. Guess I'm going to have to pony up for some shop time.

 

[Dustin Jackson]

@Clack There are fake parts shipped and labeled as GM Genuine.

I had to pull a brand new “gm genuine” TPS sensor out of my 94 1500 yesterday because I was stuck in 3rd gear. Put a junkyard TPS back in it and I can drive it again.

 

[j91z28d1]

Both OEM correct parts. No reason to believe they were not genuine. https://www.amazon.com/dp/B01FRENAA0?psc=1&ref=ppx_yo2ov_dt_b_product_details

I'm no good on electrical stuff. Wouldn't know how to check continuity. Guess I'm going to have to pony up for some shop time.

that's literally the exact same "oem" sensor I bought off Amazon and had to change it a few months later over wackyness. I'm 99% sure it's counterfeit or at least from a bad batch. sort by 1 or 2 star reviews and scroll thru.

here's a pic.. left is the original from 2011 middle is the Amazon, right is new from a local dealer. they look exactly the same except for the font on the laser printed part number is different.

I no longer trust it to save 20$ local dealer will. usually match or very close to gm parts direct price if you ask them too

 

[Clack]

Damnit! They trick me!! I read the 1 star reviews. My last amazon one was leaking out of the top of the sensor too!! Now I need to sacrifice my hand again because I thought I could save $50.

 

[j91z28d1]

Damnit! They trick me!! I read the 1 star reviews. My last amazon one was leaking out of the top of the sensor too!! Now I need to sacrifice my hand again because I thought I could save $50.

it's so annoying right.. I mean it might not even be it, but you kinda gotta rule it out before tearing into the engine.

other thing you can do it pick up a mechanical gauge that goes in down on the front drivers side of the engine and check there.. that tests the pressure straight off the pump before going thru all the filter stuff.

 

[Dustin Jackson]

Here are some pictures of the fake GM Genuine part

 

[Rocket Man]

Damnit! They trick me!! I read the 1 star reviews. My last amazon one was leaking out of the top of the sensor too!! Now I need to sacrifice my hand again because I thought I could save $50.

That part was sold by a company called “ click, buy, love” and only shipped by Amazon. If you’re buying parts online, you’re best to buy from a well known seller like Rock Auto os possibly if it’s sold by Amazon and not a third party seller on Amazon. Even then, I’ve heard of returns from the bad sellers getting mixed in with genuine Amazon returns and then being resold by Amazon themselves. I always read reviews also. Good you figured it out.

 

[Rocket Man]

Also, any time you’re buying an $80 part for $20….ahem.

 

[j91z28d1]

Also, any time you’re buying an $80 part for $20….ahem.

well to be fair, the dealer parts are horrible over priced. I once bought a vw switch that was over 100$ at the dealer but made in a China factory that sold stright off aliexpress as well. it was 16$ with a pig tail that. I do believe it wasn't counterfeit either. so price isn't always the best indicator. gm parts direct well sell it for much cheaper, and so far my local dealer has been willing to match their list price, saving shipping.

might not hurt that I try to go after work while in uniform so I look like a mechanic. but still, lotta meat on the bones of a 10$ to make sensor selling for 80$.

I still would love to know how they get the packaging perfect looking. unless they just buy from a contact at the same place gm gets them.

 

[Rocket Man]

well to be fair, the dealer parts are horrible over priced. I once bought a vw switch that was over 100$ at the dealer but made in a China factory that sold stright off aliexpress as well. it was 16$ with a pig tail that. I do believe it wasn't counterfeit either. so price isn't always the best indicator. gm parts direct well sell it for much cheaper, and so far my local dealer has been willing to match their list price, saving shipping.

might not hurt that I try to go after work while in uniform so I look like a mechanic. but still, lotta meat on the bones of a 10$ to make sensor selling for 80$.

I still would love to know how they get the packaging perfect looking. unless they just buy from a contact at the same place gm gets them.

The packaging is never perfect but you have to know what to look for. You’ve never heard of the multibillion dollar industry of Chinese counterfeiting that’s been happening forever? There’s been a huge amount of AC Delco plugs lately that were shown by experts to be fake. Here, look at these “Ray-Ban” sunglasses I bought. The only way I can tell they’re fake is because:

1.I paid $20 for a pair that sell for over $200.
2. They came directly from a Chinese seller, shipped DHL from there. They took a month to arrive.

They look exactly like the real thing TO ME. I’m not sure if anybody other than an expert can tell. Even the cleaning rag has a perfect logo and feel.

Edit: Google “ counterfeit AC Delco spark plugs” you’ll see.

 

[j91z28d1]

I guess that's true, been fake everything else for years. I've just never really cared about buying oem parts till lately as it seems life time warranty at local parts stores aren't really life time anymore, and their parts seem to have gotten really bad too. that and Amazon / ebay has given them easy outlets to sell them, before only dealers really sold dealer parts.

for years I've always just bought what had a lifetime at my local parts store, never was a problem back in the day. now, not so much haha

 

[Indy1K]

it's so annoying right.. I mean it might not even be it, but you kinda gotta rule it out before tearing into the engine.

other thing you can do it pick up a mechanical gauge that goes in down on the front drivers side of the engine and check there.. that tests the pressure straight off the pump before going thru all the filter stuff.

I just replaced the Oil pressure sensor with the HIHIAV part from Amazon. Now my hot idel pressure is maybe 15psi and driving around 20-25psi. I think this sensor is questionable.
Do you have a picture of where you can screw in a mechanical oil pressure gauge into the driver side of the engine? Thanks in advance,
Kevin

 

[j91z28d1]

I just replaced the Oil pressure sensor with the HIHIAV part from Amazon. Now my hot idel pressure is maybe 15psi and driving around 20-25psi. I think this sensor is questionable.
Do you have a picture of where you can screw in a mechanical oil pressure gauge into the driver side of the engine? Thanks in advance,
Kevin

I can't find the video I saw on it. but this prime video shows the port with the engine in a stand and in the description he shows the adaptor thread and stuff if you're not buying a gauge kit with them already in it.