More Oil Pressure Wackiness

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Clack

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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

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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

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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

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

j91z28d1

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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.
 

Dustin Jackson

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@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

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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
 

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Clack

Clack

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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

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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.
 

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