What does this code mean?
The controller finds an oil-pressure sensing/performance concern. A signal problem and genuinely low mechanical oil pressure must be distinguished; replacing the sensor on the code alone can miss the underlying fault. GM's cited example requires electrical/sensor checks and then a mechanical pressure test under specified hot-idle conditions.
Sources and interpretation [1]
A code identifies a detected condition, not a part that must automatically be replaced.
Before replacing a part
If an oil-pressure warning or abnormal engine noise is present, stop safely and follow the owner's manual. Have pressure verified using the correct test port and engine specification; a threshold or reading from another port or engine is not interchangeable.
Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
P0521Engine Oil Pressure Sensor PerformanceManufacturer communications
8Original wording in English
BUICK, CHEVROLET
Reported code forms P0521
This Preliminary information communicates to the dealers information related to potential failed engine camshaft cover causing excessive engine oil consumption, blue smoke from the exhaust system at low mileage. Can…
BUICK, CHEVROLET
Reported code forms P0521
This Preliminary information communicates to the dealers information related to potential failed engine camshaft cover causing excessive engine oil consumption and blue smoke from the exhaust system at low mileage. Can…
BUICK, CHEVROLET
Reported code forms P0521
This Preliminary information communicates to dealers engine wiring harness inspections and engine oil pump diagnostic testing related to MIL on with P0521, P06DD or P06DE.
BUICK, CHEVROLET
Reported code forms P0521
Emission Recall. General Motors has decided to conduct a Voluntary Emission Recall involving certain vehicles. The Engine Control Module (ECM) may not clear the permanent status of DTC P0521 (Engine Oil Pressure Sensor…
BUICK, CHEVROLET
Reported code forms P0521
Service Update. In certain vehicles, if the Engine Control Module (ECM) sets the DTC P0521 (Engine Oil Pressure Sensor Performance), the ECM cannot clear the permanent status of this DTC. If the ECM had previously set a…
BUICK, CHEVROLET
Reported code forms P0521
This Preliminary information communicates to the dealers information related to isolating a potential engine wiring harness issue causing a MIL on with P0521.
Check vehicle applicability
5A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Sources and interpretation
These explanations are editorial summaries of the linked manufacturer material. PDF page numbers count from the first file page. Original publications are in English; translations are reference aids. A cited edition is not a claim that it is the manufacturer's latest instruction.
- 24-NA-173 · P0521, engine oil pressure sensor performance ↗
General Motors · PDF page(s) 1, 2 ·
Source check date · 2026-10-27
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.