2013 Chevrolet 1500 5.3 VIN 1 LC9 oil pressure light with P0521

Dave Owner Florida Posted   Latest   Edited  
Unsolved
Electrical
2013 Chevrolet Silverado 1500 LTZ 5.3L (7 LC9) 6-spd (6L80) — 3GCPKTE74DG360325
P0521 — Engine Oil Pressure Sensor/Switch "A" Range/Performance
Oil Pressure Light

Hello everyone. Vehicle has had 2 oil pressure sensors and screens replaced, the connector and by passed the OE harness with an overlay directly to the PCM to eliminate harness and original connector. Mechanical pressure never drops below specifications and never higher than pressure relief specs. DTC only sets in mid range RPM's (1300 to 2200) while driving, will not set in service bay. Suspect an internal PCM logic problem. Any one run across this or have any thoughts?

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William Technician
West Virginia
William Default
   

Has the oil pump pick-up tube o-ring been inspected? I see a lot of these with squared-out o-rings. Mahle makes an oversized o-ring just for this on their oil pumps. I doubt the PCM is faulty.

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Eddy Business Development Manager
California
Eddy Default
 

I second this. Outside of the obvious like trying a factory oil filter, and verifying leaks in the valve cover baffle (TSB PIP5276F), I would inspect that O-ring. It is very common for them to be split

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Dave Owner
Florida
Dave Default
 

Not denying this as a common problem, but everyone we have seen had some kind of change in pressure when tested. The pressure is always with in specifications, cold and hot. We would think that we would see a mechanical change, right? But to answer, no we have changed the pick up tube oring but OE filter is on currently. Thanks guys

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Mark Engineer
Colorado
Mark Default
 

Dave I agree with William and Eddy probably the O-ring on pickup tube. To confirm this I took an old sending unit, I took out the guts, tapped it for 1/8 NPT and screwed in the hose for my oil pressure gauge. I taped the gauge to the windshield and screwed into where the regular sending unit is installed. Took a test drive. Gauge showed all. One last thought a second cam bearing worn and…

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Obie Technician
Washington
Obie Default
 

Many oil pressure indicators that are controlled thru modules do not report quickly or even accurately! Mechanical testing is required before condemning any module.

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Marvin Mechanic
Mississippi
Marvin Default
 

You say mechanical pressure you mean another guage installed or the one in dash??

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Dave Owner
Florida
Dave Default
 

Yes Marvin, actual mechanical engine oil pressure with a testing gauge. At the oil filter with an adapter and intake manifold oil pressure sensor port.

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Marvin Mechanic
Mississippi
Marvin Default
 

Overfill till it would cover the pickup oring and see if goes way

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Jim Owner/Technician
North Carolina
Jim Default
 

William is right- put an oil pickup o-ring on it, common problem on these.

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Rick Mechanic
Washington
Rick Default
 

Dave, I think I would find a way to hook up test set up that would allow me to hook up both a mechanical and the electrical sensor at the same time. This way I could watch the mechanical oil pressure as I was driving it and see what happens when it sets the code. That way I would be positive weather was an oriole pressure issue worn electrical issue. Good luck

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Scott Mechanic
Saskatchewan
Scott Default
 

I’ve seen the passage between the filter and eop switch get plugged, also oil filter being plugged. When I change the switch, I pull the screen out, oil filter off and clear the passage.

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Alan Owner/Technician
Mississippi
Alan Default
 

I agree with William that's where you need to start

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Andrew Diagnostician
Michigan
Andrew Default
 

I have also seen VLOM issues causing low pressure at the sensor.

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Paul Mechanic
Illinois
Paul Default
 

At first I was thinking it can't be the pick up tube o ring as a few have suggested as you stated your are monitoring oil pressure where sender resides and would you would see if pressure drops down, but then I thought you said it only happens driving and not in bay, perhaps they are correct as oil is sloshing away momentarily- not sure if you took vehicle driving with gauge connected to where…

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Jesse Owner/Technician
Pennsylvania
Jesse Default
 

The thought occurred to me after reading all this this engine should have cylinder cutout system on it Andy variable valve timing system it would take two people to properly do this but with a scan tool hooked up watching the oil pressure and the cylinder cutout system and under late mid throttle while driving steady state will put the cylinder cut out 1 the mechanical pressure gage at the oil…

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Scott Owner/Technician
Missouri
Scott Default
 

Go to Napa and get a cheap oil filter and screw it on. Then retest. Never had one set a code though, always shows low pressure.

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Andrew Technician
Wisconsin
Andrew Default
 

With a P0521 it probably is experiencing a loss of oil pressure in the top end and at the sensor. Putting a gauge on it can be misleading because when using an oil filter adaptor in place of the filter it takes the filter out of the equation and reduces the resistance in the system allowing the pressure to increase ever so slightly. Also the reason that the larger PF63 is recommended. It’s…

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Mark Engineer
Colorado
Mark Default
 

Andrew Excellent description of the oil path/system. Thanks for sharing your experience (the next time I “swing” a reman engine in I plan to pull that rear cover to look at the dumbbell looking valve on the core engine)

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Andrew Diagnostician
Michigan
Andrew Default
 

Thank you for this description. Something I'm going to continue looking for.

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Sean Diagnostician
Saskatchewan
Sean Default
   

Here is a picture of what Andew is refering to. Part number …

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Paul Mechanic
Illinois
Paul Default
 

If you suspect it may be the afm system when enacted dropping oil pressure, drive it in 5M if it's the six speed trans which will keep it from coming in, then if you don't code, you ll know where to concentrate your diagnosis.

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