What Does Code P0521 Mean?
- P0521 definition: Engine Oil Pressure Sensor/Switch Range/Performance
- Issue Severity: SEVERE – Stop driving immediately
- Repair Urgency: Fix this code immediately (same day if possible) to avoid internal engine damage.
- Diagnosis: Initially, this trouble code will not stop your vehicle from operating normally. However, if not addressed early on, this code can cause serious internal damage to your engine causing complete engine failure. It is recommended to take your vehicle to the nearest dealership as soon as possible to have this code properly repaired to avoid costly engine repair(s).
The oil pressure sensor calculates the oil pressure of the vehicle’s engine. This is then communicated to the ECM in the form of a voltage value. The P0521 code is set when the ECM detects the voltage value is either higher or lower than the specified acceptable range of oil pressure. This code can also be set when the engine detects constant fluctuation of the oil pressure value.
P0521 Causes
There are many potential causes of code P0521.
- Faulty oil pressure sensor (sometimes called an oil pressure sending unit)
- Faulty wiring/connections
- Short or open ground in the wiring
- Blown Fuse
- Engine coolant temperature sensor is not operating correctly
- Faulty Power Control Module
P0521 Symptoms
- Check engine light
- Oil pressure warning light
- Oil pressure gauge too high/low
- Engine stall
How Do I Fix Code P0521?
With an oil pressure sensor fault, the first step is to get it diagnosed to figure out what is causing the problem.
If your vehicle has this fault and you’re not comfortable diagnosing this issue at home, we recommend finding a RepairPal certified shop nearby to pinpoint the problem and give an accurate estimate for repairs.
These shops can not only help you figure out what’s going wrong before you waste time and money on the wrong parts, but they also offer a minimum 12-month, 12,000-mile warranty and stand behind all their estimates with guaranteed fair pricing.
> Find a RepairPal Certified Shop Near You
How Much Does It Cost to Fix Code P0521?
P0521 can be caused by anything from a low oil level to a bad oil pressure sensor to a leak or clog in your oil lines. It’s impossible to give an accurate estimate without properly diagnosing the issue first.
If you take your car to a shop for diagnosis, most shops will start with an hour of “diag time” (the time spent in labor diagnosing your specific issue). Depending on the shop’s labor rate, this typically costs somewhere between $75-$150. Many, if not most, shops will apply this diagnosis fee to any required repairs if you have them perform the repairs for you. From there, a shop will be able to give you an accurate estimate for repairs to fix your P0521 code.
Possible Repair Costs for P0521
For error code P0521, one or more of the below repairs may be needed to solve the underlying issue. For each possible repair, the estimated cost of repair includes the cost of the relevant parts and the cost of labor required to make the repair.
- Top off oil: $5 to $10
- Oil and filter change: $136 to $149
- Oil pan replacement: $654 to $740
- Oil pressure sensor: $123 to $140
DIY Steps to Diagnose Code P0521
Engine code P0521 could be caused by a number of things, including a bad oil pressure sensor, clogged oil lines, or just a low oil level. If you’d like to try to fix code P0521 at home without throwing money at parts, you’ll want to follow the steps below for proper diagnosis. Keep in mind this is an intermediate-level diagnosis and repair and not recommended for beginners. Diagnosis requires more specialized equipment beyond what the FIXD Sensor can provide and it can be a time and labor-intensive process for inexperienced DIYers.
DIY difficulty level: Intermediate
This repair requires mechanical knowledge and is not recommended for beginners.
Tools/parts needed (our top picks from Amazon):
STEP 1: USE FIXD TO ENSURE NO OTHER ENGINE CODES ARE PRESENT.
Use FIXD to scan your vehicle to verify P0521 is the only code present. If other codes are present, they must be addressed first.
STEP 2: CHECK OIL LEVEL.
Use the dipstick to check the oil level of your vehicle. It should be between the Full and Add markings on the dipstick.
STEP 3: CHECK OIL FILTER AND DRAIN PLUG.
Verify the oil filter and drain plug are secure with no leakage. A leaky drain plug can be caused either by the plug itself, or damaged threads where it screws into the oil pan. In this case, the entire oil pan may need to be replaced.
STEP 4: INSPECT OIL PRESSURE SENSOR WIRING.
Visually inspect the wiring around the oil pressure sensor for disconnected or damaged wires.
STEP 5: CHECK OIL PRESSURE SENSOR VOLTAGE.
Using FIXD Live Data, check the oil pressure sensor voltage to ensure that it is within the specified range.
STEP 6: REPLACE OIL PRESSURE SENSOR.
If the problem persists, consider replacing the oil pressure sensor.
Common P0521 Diagnosis Mistakes
Prematurely replacing the oil pressure sensor without visually inspecting the wiring of the oil pressure circuit for disconnection or damaged wires.
Still Need Help Fixing Code P0521?
If you’ve followed the steps above and are still experiencing check engine code P0521, please contact the FIXD Mechanic Hotline if you’re a FIXD Premium subscriber or find a RepairPal certified shop near you to get the right repairs at a fair price.
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Fixed It But The Check Engine Light Is Still On?
Check engine light sometimes need to be reset manually, check out our article:
How to Reset Your Check Engine Light | 4 Ways To Clear It (With or Without a Scanner)
Recovering autocross and track day enthusiast. Once turned a VW Jetta into a pickup truck. Lives in a van down by the river. Dream car: 2001 Subaru WRC rally car.
32 Responses
This tool worked as advertised …….. I’ve had it for a year before I needed it. Used it on my daughters Silverado and sure enough P0521 code popped up she doesnt check oil
I was driving from ATLANTA to NJ, oil light and engine warning sound came on, i checked the oil before leaving, its a 2009 tahoe hybrid… I pulled over in VIRGINIA, rechecked the oil it seemed to be a little low added a quart and half of oil, rechecked it, oil level was fine… Ran the truck with FIXED and i was still getting the code po521, it was 3:00am, no mechanics around anywhere.. Rechecked the oil, loose wiring, any leaks or weird sounds, found nothing abnormal, prayed to GoD for a long time, started the truck back up, light went off came back on after some miles, I just kept the faith, 3hrs later, the oil pressure gauge read correct reading, engine oil light went off and the engine light, truck was still driving great, made it home 2 1/2 hrs later with no sign of any issue, still going to have it checked out after rechecking with FIXED and take it to a mechanic just to be on the safe side, good luck everyone… I guess GOD fixed mine 🙂
Hi Darcy: i have the same pickup 2007/2008 gmc sierra with the 6.0l vortec max and have that exact same problem have you been able to solve the problem with all that you have done how can get contact with you
If p0521 keeps popping up, it’s not just a sensor or low oil level. Did both of those to no avail. Had to change my whole oil pump. While I was in there, changed out the rod and main bearings. I have split Year’07/‘08 GMC Sierra with the 6.0 Vortec Maxx. 2 years out, still running. I have almost 300k on this truck!
Awesome to hear, Darcy! Thank you so much fo this tip. Happy and safe driving! 🙂
About how much should it cost to replace the oil pump on a 6.0? I replaced the oil pressure sensor & filter & the O-ring on the p/u tube & still have low pressure on my gauge but no check engine or warning lights have come on, I hate to spend $ for any unnecessary repairs, any advice would be appreciated.
Hi Troy: can you write more about what you mean by GASCAPSL do not understand what you mean google translates errors?
have the same error 521 on my Tahoe 2007 has change sensor / filter / oil
errors come again vh. leif Danmark cobenhagen
Check your gas cap! You might be surprised!
Hi, Check engine light on my dash, replaced the oil pressure sensor along with the small filter on my 2012 Tahoe. The check engine light disappeared after replacing the sensor but after driving couple of miles it came back up again, I deleted it and after couple of days showed up again and never went away. Any suggestions please thank you…
Did you ever come up with anything? I brought it to the dealer. They charged me $500. It’s back on. They wanna do $1200 more of exploratory work with no idea if it will work I’m so frustrated.
Just had my oil pressure sensor changed out including the filter that goes in there too light turned off and just came back on oil level is good what else could be the problem? 2013 Chevy Silverado 1500
I’m having same problem now what did yours end up being
Did you ever come up with anything? I have the same problem.
I have a 2013 GMC with same problem
I have FIXD and had this error code pop up earlier this year on my GMC Sierra. I took it to the dealer and they ran diagnostics on it and came up with the same error. They replaced the sensor and did an oil/filter change. Nine months later I get the same error message again. It seems strange that the sensor went “bad” again so soon. Looks like I’m going back to the dealership again.
Terry, with my experience with these new generation engines. Their is an o ring at the bottom of your oil pump that connects the oil pump and pick up tube that goes bad and you won’t get the oil pressures that you should.
FIXD has been a big help to me as I do work on my Trail Blazer myself . Some were a pain but I adhered to fixing the problems at hand, a great product !
I have 13 silverado and had this code pop up a month ago and it was oil sensor so jba fixed the issue. But now the ck eng light came back on with same code 521, oil level great no leaks under truck and my question is when the sensor was replaced does it also come with the filter or screen that sapposed to get replaced under the sensor. Im just wondering if they replaced it when doing sensor.
Took my car to dealer. They replaced switch. Continued my trip. Stopped for gas and check engine light came back on as I accelerated to enter highway.
Po521 code on 07 trailblazer with 140k miles. Scanner says oil pressure voltage too high. Have changed sensor and screen, wire between ecm and sensor, changed oil and filter, oil pressure gauge in dash and still get 521 code. Vehicle runs great other than check engine light for oil pressure. Would pull my hair out if I wasn’t bald. Lol. Any ideas?
Ran the synthetic oil passed the oil life mileage. Oil pressure reading about 20-25 psi. Changed oil and filter and oil pressure reading 40-50 psi. Removed code and has not come back.
I like fixd has been on point every time great to have
Took my car to my mechanic after using my FIXD to diagnose the check engine light which appeared very suddenly on my car. After FIXD showed a code of P0521, I took my vehicle to my mechanic. His sophisticated system showed the same code and the oil pressure pressure switch was replaced. Very happy that I purchased the FIXD and also purchased some for other members of my family. Thanks for an excellent product.
That’s awesome Max! So glad we could help!
FIXD Team
oil level was low. raised oil level to proper amount .erased code .SEEMS TO BE OK NOW.
What was the final thought. I have been having the same problem. Light came back on. The dealer changed the oil pump, sensor, screen and oil change. Was good for 1 year. 1 year and 1 month after the warranty expired. Light Popped back up. I changed the sensor myself this time. Light went away and came back up again. Oil level is good.
I’m having the exact same problems!
Hi everyone. I need help or advice. I recently had my check engine light on..I had code P0521. Changed oil pressure sensor to same factory one and the little filter also. 3 days later I have check engine light and it’s the same code. Oil level reads good on dip stick. Any ideas or suggestions?? Please. Thanks everyone.
Did your issue go away?
This code has made its ugly appearance whilst using my FIXD scan tool on my svz but my check powertrain warning is displayed on the dash computer next to my engine light can anyone confirm that the code and computer warning on dash are in direct relation to each other or am I looking at two different issues?
i had a powertrain warning ended up being a fuel injector was faulty
Check your gascaps! You might just be surprised!!