AutoCodes – GMC – P0521 GMC

P0521 GMC 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 GMC 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 31,889

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
FAQs
Comments
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Code P0521 GMC 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 GMC - Engine Oil Pressure Sensor Performance - AutoCodes.com — P0521 GMC Code - Engine Oil Pressure Sensor Performance

What does this mean?

What are the Possible Causes of the DTC P0521 GMC?

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 GMC?

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.

There is a factory service bulletin for the following GMC models:
2007-2010 GMC Sierra
2007-2010 GMC Yukon
2005-2009 GMC Envoy
GMC Factory Service Bulletin OBDII Code P0521

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0521 GMC 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 GMC code?

Need more information on how to fix the P0521 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0521 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P0521 2014 GMC Sierra — Engine Oil Pressure Sensor Performance
P0521 2015 GMC Sierra — Engine Oil Pressure Sensor Performance
P0521 2016 GMC Sierra — Engine Oil Pressure Sensor Performance
P0521 2017 GMC Sierra — Engine Oil Pressure Sensor Performance
P0521 2018 GMC Sierra — 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.

Frequently Asked Questions about P0521 GMC Code

1. What are the common symptoms of OBDII code P0521 in a GMC vehicle?

Symptoms may include low oil pressure readings on the gauge, illuminated oil pressure warning light on the dashboard, engine knocking or ticking noises, and possible engine performance issues.

2. What are the possible causes of OBDII code P0521 in a GMC vehicle?

Common causes of this code include a faulty engine oil pressure sensor, wiring issues such as shorts or opens in the circuit, low engine oil level or pressure, or a malfunctioning oil pump.

3. How can I diagnose the cause of OBDII code P0521 in my GMC vehicle?

Diagnosis typically involves using a scan tool to read the code, checking the engine oil level and pressure, inspecting the wiring and connector of the oil pressure sensor, and testing the sensor itself for proper operation.

4. Can I continue driving my GMC vehicle with OBDII code P0521?

It is not recommended to drive your vehicle with this code as it indicates a potential issue with the engine oil pressure system, which can lead to serious engine damage if not addressed promptly.

5. How can I repair OBDII code P0521 in my GMC vehicle?

Repair options may include replacing the engine oil pressure sensor, repairing any damaged wiring or connectors, ensuring the engine has proper oil level and pressure, and verifying the oil pump is functioning correctly.

6. Is it safe to reset the OBDII code P0521 in my GMC vehicle without addressing the underlying issue?

Resetting the code without fixing the root cause may temporarily turn off the warning light, but the issue will likely reoccur, potentially leading to more severe engine problems.

7. Can a DIY enthusiast fix OBDII code P0521 in a GMC vehicle?

Depending on your skill level and access to tools, you may be able to replace the engine oil pressure sensor yourself. However, diagnosing and fixing other potential causes may require professional assistance.

8. How much does it typically cost to repair OBDII code P0521 in a GMC vehicle?

The cost of repair can vary depending on the exact cause of the code and whether you perform the work yourself or take your vehicle to a mechanic. Budget for parts and labor costs associated with sensor replacement or other necessary repairs.

9. Will OBDII code P0521 cause my GMC vehicle to fail an emissions test?

If the code triggers the check engine light, it may cause your vehicle to fail an emissions test, as the system is designed to detect and flag issues related to emissions control and engine performance.

10. Is OBDII code P0521 specific to GMC vehicles only?

No, OBDII code P0521 related to Engine Oil Pressure Sensor Performance is a generic code that can appear in vehicles from various manufacturers, not limited to GMC.