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P0521 won't go away.

 
Old 01-25-2019, 06:44 PM
  #1  
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Default P0521 won't go away.

I originally got code p0521 a few months back when I remote started It. I would come out and find the car off and engine light on when I put the key In. First thing I did was replace the oil pressure sending unit twice with a advance auto one. After the code came back the third time I replaced It with a OEM AC Delco one and replaced the little filter screen under the sensor. Code disappeared for 3 weeks and came back. So I read and found a TSB gm released saying to use the performance version of the AC Delco oil filter If you have the DOD/AFM system. I put that filter In yesterday UPF48R and this morning leaving work I remote started It and just sat In It and It ran the full 10 minutes without Issue. After starting It a second time It ran for 10 seconds and shut off and the code came back. I'm currently running Castrol Edge Full Synthetic 5w30 and a Performance AC Delco oil filter, which I believe Is the same as Mobil 1 which I just replaced yesterday. When I was using the K&N oil filters I never had this problem. I also heard about sludge and took the valve cover off and the engine Is spotless Inside. The AFM works fine. I always change the oil when It gets down to 40 or 30%. And the engine sees high RPM on a daily basis and performs extremely well and doesn't use any oil. So that's why Im stumped. Also It only happens when the engine Is cold never when warm. I even started It with the key and let It run and that will sometimes cause the code to pop up. But the other morning It was cold out and It ran the full 20 minutes on remote start without setting the code. 2008 Impala SS
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Old 01-25-2019, 11:33 PM
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Get a mechanical oil pressure check, if you replaced the senor three times that's not the issue. Could be the wiring to the switch though, The cars 11 years old. Stop beating it till you figure it out. Whats the mileage?.
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Old 01-26-2019, 12:10 AM
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Originally Posted by rottonj View Post
Get a mechanical oil pressure check, if you replaced the senor three times that's not the issue. Could be the wiring to the switch though, The cars 11 years old. Stop beating it till you figure it out. Whats the mileage?.
It just hit 150k and yeah I'm gonna hook up a gauge later on. The only problem Is It only happens when cold, so I would have to let It completely cool off and then check. I seriously don't think the problem Is Internally because It was -10F and again It ran the full 20 minutes without Issues. I'll update when I check It with a mechanical gauge.
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Old 01-30-2019, 09:56 PM
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The gauge set I bought didn't have a test fitting for the LS4. I let It Idle for about 40 minutes as It was -15 all day and It ran fine and didn't set a code. Gonna swap back to K&N filters and see If that cures the problem.
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Old 01-31-2019, 08:00 AM
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This is supposed to be a quality piece, I do not own this so be sure if you consider it check to be sure it fits your application. Post back your findings once you get this resolved.

https://www.glowshiftdirect.com/oil-...mm-1-5-thread/

Also this forum has lots of good info on oil , filters and everything in between related. Opinions on the site vary, so take that for what its worth. You will have to join to search.

https://www.bobistheoilguy.com/forum.../forum_summary
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