2011 Tahoe with error Code P0521

speedracerx64 · March 19, 2015

I picked up a used Tahoe at the end of February with 61,700 miles on it. The night I purchased it, the CEL came on about 50 miles into the trip home. I took it over to Advance Auto to allow them to scan and retrieve code for me, which ended up being code P0521, engine oil pressure out of range. I took it to a local certified GM dealer for the warranty issue, since I purchased a "certified" vehicle. The shop hooked the Tahoe up on the diagnostics machine, reflecting the code I reported to them. The tech. replaced the oil pressure sensor. The same day I picked up the Tahoe, I drove it to work to observe the oil pressure, and much to my dismay, the idle reading was around 12 PSI and 20 PSI was the maximum reading at 60mph. After work, upon starting the Tahoe, the CEL reappeared. This time, I contacted OnStar for a diagnosis, and once again, the code P0521 appeared. The Tahoe was returned to the same local GM dealer to address the problem. GM Customer service was contacted prior to the first shop visit, since the service writer gave me a hard time about having to confirm the vehicle was indeed under warranty. GM Customer Service opened a file on my behalf.

After the second visit to the shop, the tech replaced the oil pump. I picked up the truck today, and upon arrival at my place of employment, the CEL came on again. OnStar once again confirmed the code was P0521. OnStar advised to tow the Tahoe to the shop, and sent out a rollback to pick it up.

To sum it up, this is the third time the Tahoe has gone into the shop for the same issue. GM Customer Service has been made aware of this.

Reading some of the other stories on this forum, as well as other auto-related sites, it appears that this oil pressure problem can be a "black hole" of issues. I will update as details unfold.

02suburbanZ71 · March 19, 2015

Take it back. Period.

speedracerx64 · March 20, 2015

My update is as follows: the shop is unable to recreate the issue which is causing the code, per the service writer. The service writer asked permission for a tech to take it to their home this evening to see if the CEL will reappear, and note under what conditions. I'm not too thrilled with that, and the shop assured me that they would take full responsibility for it, as my insurance will for their loaner they gave me (a sedan affiliated with a now-defunct division of GM, with over 100,000 miles, which shakes, a ripped and damaged front bumper cover, and a suspension that feels like it has been used as a curb hopper). Yes, the service writer definitely feels my pain.

02suburbanZ71 · March 20, 2015

Call the district service MGR, take it to another dealer! Get ANGRY [emoji35][emoji35]

speedracerx64 · March 20, 2015

Thank you for the suggestion. I'll contact the District Manager tomorrow.

02suburbanZ71 · March 20, 2015

Be sure to post back. Demand answers

speedracerx64 · March 20, 2015

I didn't have to contact the district service manager, after all. The shop was unable to reproduce the code, however, the oil pressure was increased, to the 30-40 psi range. Kudos to the techs! Keeping fingers crossed that the replaced items solved the issue. I will update if anything changes.

sahls01gmc · March 20, 2015

I would ride a fine line between being stern and getting angry. Rest assured that your warranty will cover you, and let the dealer take care of it. I know it's not the best scenario, but you are also buying someone else's "old" vehicle.

Post up some pics of it now!

Cosmic Charlie · March 20, 2015

Not that it matters now BUT I'll bet the people that sold you the Tahoe KNEW about the issue and STUCK YOU WITH IT - harldly a coincendence, and not that nice to to that -

When buying used have someone plug it in and check for codes, even if the code was erased it WILL show as historical and then re-appear as a CEL after some miles (about 50 ?) & so many re-starts ... at least you'll know before paying ...

Hope your prob is solved ...

Sir Dan · March 21, 2015

Lot of GM truck owners are seeing this low oil pressure issue come up lately on the 5.3L engine. It seems there is a filter screen for the fancy new AFM (active fuel mgmt) located under the oil pressure sensor that plugs up and causes the low reading while the pressure is actually fine. It would seem like an easy fix...just pop out the sensor, pull the screen for a cleaning and off you go but it is located way on the back of the motor and nearly impossible to get at without pulling the intake manifold. Another fail for GM.

speedracerx64 · March 30, 2015

Just a quick update, it appears that the oil pump replacement resolved the issue. No more CELs.

Roger heggie · February 24, 2020

I test drove a 2012 1500 Silverado Feb 2019 leaving the dealership the check engine light came on and the oil pressure was at zero took back to them they insured me it was just the oil pressure switch this was a Friday afternoon on Tuesday following week o got a call the salesman called and said the truck was ready I took it out again it drove nice ood oil pressure so bought had it two weeks it engine light came on code 521 low oil took it back it took 2 weeks to get back they replaced the sender and screen and roughly 2 months after repair it did it again code 521 took back this time they put and oil pump in it drove 5 months my friendly light appears again code 521 at this point I have owned it for 10 months I take it back once I get home I get a call from service manager asking when was the last time I had oil changed I told him I did about a month ago and I used 5w30 mobile one syn and a six filter at that time he stated that was why it threw the code 521 because I didnt use dextrose and ac delco filter I laugh and said Mobil one is a very good oil and six is one of the best he held his ground and talked me into letting them change the oil to gm products I said that wont fix it next day I get a call and I'm told its ready and my bill was 380.00 I lost it with them and after cooling off I asked why I was paying 50 for oil change that I did agree to that but 330.0 was parts and labor for the tek to replace the screen for the afm I asked him why am I paying for and issue that this lemon has had since I frist drove it and there bandaid didnt fix so I left only paying 50 for the oil it's been just over one month since the last time they had it and there is 55% left to the oil life and my old friend came to visit 521 looking for input unfortunately 8 months ago I got deamd disabled and have no in come now I need the truck no bank will give me a loan without a job i would love to stuff the truck up his ass but violence wont help s I'll i have to be nice last time I asked them to do the afm dod they said they cant i know why they are to dam stupid help me out plz

Roger heggie · February 24, 2020

I test drove a 2012 1500 Silverado Feb 2019 leaving the dealership the check engine light came on and the oil pressure was at zero took back to them they insured me it was just the oil pressure switch this was a Friday afternoon on Tuesday following week o got a call the salesman called and said the truck was ready I took it out again it drove nice ood oil pressure so bought had it two weeks it engine light came on code 521 low oil took it back it took 2 weeks to get back they replaced the sender and screen and roughly 2 months after repair it did it again code 521 took back this time they put and oil pump in it drove 5 months my friendly light appears again code 521 at this point I have owned it for 10 months I take it back once I get home I get a call from service manager asking when was the last time I had oil changed I told him I did about a month ago and I used 5w30 mobile one syn and a six filter at that time he stated that was why it threw the code 521 because I didnt use dextrose and ac delco filter I laugh and said Mobil one is a very good oil and six is one of the best he held his ground and talked me into letting them change the oil to gm products I said that wont fix it next day I get a call and I'm told its ready and my bill was 380.00 I lost it with them and after cooling off I asked why I was paying 50 for oil change that I did agree to that but 330.0 was parts and labor for the tek to replace the screen for the afm I asked him why am I paying for and issue that this lemon has had since I frist drove it and there bandaid didnt fix so I left only paying 50 for the oil it's been just over one month since the last time they had it and there is 55% left to the oil life and my old friend came to visit 521 looking for input unfortunately 8 months ago I got deamd disabled and have no in come now I need the truck no bank will give me a loan without a job i would love to stuff the truck up his ass but violence wont help s I'll i have to be nice last time I asked them to do the afm dod they said they cant i know why they are to dam stupid help me out plz

carnau · February 25, 2020

22 hours ago, Roger heggie said:

I test drove a 2012 1500 Silverado Feb 2019 leaving the dealership the check engine light came on and the oil pressure was at zero took back to them they insured me it was just the oil pressure switch this was a Friday afternoon on Tuesday following week o got a call the salesman called and said the truck was ready I took it out again it drove nice ood oil pressure so bought had it two weeks it engine light came on code 521 low oil took it back it took 2 weeks to get back they replaced the sender and screen and roughly 2 months after repair it did it again code 521 took back this time they put and oil pump in it drove 5 months my friendly light appears again code 521 at this point I have owned it for 10 months I take it back once I get home I get a call from service manager asking when was the last time I had oil changed I told him I did about a month ago and I used 5w30 mobile one syn and a six filter at that time he stated that was why it threw the code 521 because I didnt use dextrose and ac delco filter I laugh and said Mobil one is a very good oil and six is one of the best he held his ground and talked me into letting them change the oil to gm products I said that wont fix it next day I get a call and I'm told its ready and my bill was 380.00 I lost it with them and after cooling off I asked why I was paying 50 for oil change that I did agree to that but 330.0 was parts and labor for the tek to replace the screen for the afm I asked him why am I paying for and issue that this lemon has had since I frist drove it and there bandaid didnt fix so I left only paying 50 for the oil it's been just over one month since the last time they had it and there is 55% left to the oil life and my old friend came to visit 521 looking for input unfortunately 8 months ago I got deamd disabled and have no in come now I need the truck no bank will give me a loan without a job i would love to stuff the truck up his ass but violence wont help s I'll i have to be nice last time I asked them to do the afm dod they said they cant i know why they are to dam stupid help me out plz

Sounds to me like they are not blowing the trash out when they replace the screen. If they just replace the screen and the filter, the trash falls back down with no pressure and when you crank it, it just pushes the same crap back into the screen. I have seen this 1000 times. I actually made a video on how to fix this the RIGHT way. Check out this video.