P0521 on Buick
Engine Oil Pressure Sensor/Switch Range/Performance
P0521 on Buick vehicles indicates engine oil pressure sensor/switch range/performance. Au7o has documented this code across 2 Buick models — most commonly on Encore, Envision. This code indicates the engine oil pressure sensor or switch is sending a reading that is implausible or out of its normal operating range — for example, the value doesn't match what the engine's speed and conditions should produce. Unlike a simple circuit fault, this means the signal is present but doesn't make sense (range/performance). It can be caused by a failing sensor, wiring issues, or by genuinely abnormal oil pressure. Because oil pressure protects the engine, a true low-pressure reading should be confirmed and taken seriously. Typical repair costs on Buick range from $180 to $650, depending on the specific model and root cause.
Common Causes of P0521
- •Faulty or worn oil pressure sensor/switch
- •Low engine oil level or actual abnormal oil pressure
- •Wiring or connector corrosion/damage at the sensor
- •Sludge or debris affecting the sensor reading
- •Use of incorrect oil viscosity
- •Failing oil pump
- •Poor electrical ground
P0521 on Buick by Model
Buick Encore(1 issue)
- Encore GX (2020+) Three-Cylinder Turbo Stalling and Low-Oil-Pressure ECM Recall2020-2023
The second-generation Encore GX uses 1.2L and 1.3L turbocharged three-cylinder engines and has drawn complaints of reduced engine power, stalling, and lurching. GM issued a recall in which the engine control module (ECM) could fail to clear the permanent status of DTC P0521 (engine oil pressure sensor performance), masking a real low-oil-pressure condition; the remedy is an ECM reprogram. Owners also report elevated oil consumption on these small turbo engines.
Buick Envision(1 issue)
- Fuel Dilution of Engine Oil from Stuck PCV Valve (2.0T LTG / 2.5L LCV)2016-2020
On Gen1 Envisions the crankcase ventilation (PCV) valve integrated into the cam cover sticks or fails, letting unburned fuel wash past the rings and accumulate in the crankcase. Owners find the oil level rising above the full mark, a strong gasoline smell in the oil, and a rich-running check engine light. GM addressed it with TSB 18-NA-246, which pairs a PCV valve replacement and oil change with an ECM recalibration. Left alone, the diluted oil loses viscosity and accelerates bearing and timing-chain wear.
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View P0521 across all makes →Frequently Asked Questions
What does P0521 mean on Buick?▼
P0521 stands for "Engine Oil Pressure Sensor/Switch Range/Performance." This code indicates the engine oil pressure sensor or switch is sending a reading that is implausible or out of its normal operating range — for example, the value doesn't match what the engine's speed and conditions should produce. Unlike a simple circuit fault, this means the signal is present but doesn't make sense (range/performance). It can be caused by a failing sensor, wiring issues, or by genuinely abnormal oil pressure. Because oil pressure protects the engine, a true low-pressure reading should be confirmed and taken seriously. On Buick specifically, this code is documented across 2 models.
What causes P0521 on Buick vehicles?▼
Common causes on Buick: Faulty or worn oil pressure sensor/switch, Low engine oil level or actual abnormal oil pressure, Wiring or connector corrosion/damage at the sensor, Sludge or debris affecting the sensor reading, Use of incorrect oil viscosity. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0521 on a Buick?▼
Repair costs on Buick range from $180 to $650, depending on the specific model and root cause.
Which Buick models have P0521 documented?▼
Au7o has documented P0521 on 2 Buick models: Encore, Envision.