2015 Chevrolet Silverado - P0521 and Low Oil Pressure Warning

Question

Getting a 'Low Oil Pressure - Stop Engine' warning on my DIC. It usually happens when the truck is fully warmed up and I'm sitting at a red light. The gauge drops down to near zero, but as soon as I touch the gas, it jumps back up to 30-40 psi.

The engine isn't making any knocking or clicking noises, so I'm hoping it's not the actual oil pump. I change the oil every 5,000 miles with full synthetic. This truck has the Active Fuel Management (AFM) system, and I've heard those can have oiling issues.

ShopBossMike · Answer

Check the O-ring on the oil pump pickup tube. It's a very common failure on the LS/LT engines where the ring hardens and sucks air, cavitating the oil. Since your pressure is fine at high RPM, the pump is probably okay, but the O-ring is the weak link.

OBD2_Olivia · Answer

It's likely your AFM lifters are bleeding off pressure. You might need to look into a physical AFM delete kit or at least a Range Disabler to keep it in V8 mode. If the lifter seals are failing, you lose oil pressure in the upper galley.

MisfireMatt · Answer

✅ Confirmed fix: There is a tiny filter screen located underneath the oil pressure sensor that almost everyone forgets. When you replace the sensor, you MUST pull that screen out with a pick.

Mine was about 50% clogged with sludge and carbon. Even if the sensor is new, the clogged screen prevents accurate pressure from reaching it. I cleaned the port, put in a new screen (Part #12585328), and a new sensor. Pressure is now a rock-solid 25 psi at idle and 45-50 under load.

2015 Chevrolet Silverado - P0521 and Low Oil Pressure Warning

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