AutoCodes – Generic – P0521

P0521 Code - Engine Oil Pressure Sensor Performance

Quick Answer

The engine oil pressure sensor changes voltage based on the engine oil pressure. Common causes include Low oil level, Faulty Engine Oil Pressure Sensor, Engine Oil Pressure Sensor harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0521 indicates Engine Oil Pressure Sensor Performance.
Common causes: Common causes include Low oil level, Faulty Engine Oil Pressure Sensor, Engine Oil Pressure Sensor harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 38,653

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 30, 2022

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
Comments
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Code P0521 Description

The engine oil pressure sensor changes voltage based on the engine oil pressure. The engine oil pressure sensor is a 3-wire sensor comprising the signal circuit, the low reference circuit, and the 5 V reference circuit. The Engine Control Module (ECM) supplies 5 V to the engine oil pressure sensor via the 5 V reference circuit and provides ground via the low reference circuit. The ECM monitors the signal circuit of the engine oil pressure sensor to determine if the engine oil pressure sensor voltage is within the normal operating range of approximately 1 - 4 V. When the engine oil pressure is high, the engine oil pressure sensor voltage is high, and the ECM senses a high signal voltage. When the engine oil pressure is low, the engine oil pressure sensor voltage is low, and the ECM senses a low signal voltage. The ECM sends the engine oil pressure information to the instrument cluster via serial data. The instrument cluster will illuminate or display the engine oil pressure indicator when the engine oil pressure is low. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the measured oil pressure is at least 47 kPa (6.8 psi) less than or 50 kPa (7.3 psi) higher than the predicted oil pressure or the engine oil pressure is outside of a calculated working range determined by engine speed and temperature.

OBDII Code P0521 - Engine Oil Pressure Sensor Performance - AutoCodes.com — P0521 Code - Engine Oil Pressure Sensor Performance

What does this mean?

What are the Possible Causes of the DTC P0521?

Low oil level
Faulty Engine Oil Pressure Sensor
Engine Oil Pressure Sensor harness is open or shorted
Engine Oil Pressure Sensor circuit poor electrical connection
Engine Mechanical Problem
Faulty Engine Control Module (ECM)

How to Fix the DTC P0521?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

DTC P0521 can be set if engine oil pressure is outside the calculated engine oil pressure model stored in the engine control module. This can be an indication of mechanical engine issues causing lower than expected engine oil pressure.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0521 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0521 code?

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Information for Specific Makes

P0521 Buick — Engine Oil Pressure Sensor Performance
P0521 Cadillac — Engine Oil Pressure Sensor Performance
P0521 Chevrolet — Engine Oil Pressure Sensor Performance
P0521 Dodge — Engine Oil Pressure Sensor/Switch Circuit Range/Performance
P0521 GMC — Engine Oil Pressure Sensor Performance
P0521 Mercedes-Benz — Engine Oil Pressure Sensor/Switch Circuit Range/Performance
P0521 Pontiac — Engine Oil Pressure Sensor Performance
P0521 Saab — Engine Oil Pressure Sensor/Switch Circuit Range/Performance
P0521 Saturn — Engine Oil Pressure Sensor Performance

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.