Engine-CodesGMC – P128B 2015 GMC Sierra

P128B 2015 GMC Sierra Code - Fuel Rail Pressure Sensor 2 Internal Performance

Quick Answer

The P128B code in a 2015 GMC Sierra indicates a problem with the Fuel Rail Pressure Sensor 2 internal performance. Common causes include Faulty fuel rail pressure sensor, Wiring or connector issues, Fuel pressure regulator malfunction. 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
P128B 2015 GMC Sierra indicates Fuel Rail Pressure Sensor 2 Internal Performance.
Common causes
Common causes include Faulty fuel rail pressure sensor, Wiring or connector issues, Fuel pressure regulator malfunction.
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.
Table of contents Created and updated by William Orellana on Aug 19, 2024
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Code P128B 2015 GMC Sierra Description

The P128B code in a 2015 GMC Sierra indicates a problem with the Fuel Rail Pressure Sensor 2 internal performance. This sensor is responsible for monitoring the fuel pressure within the fuel rail and sending this information to the engine control module (ECM). The ECM uses this data to adjust the fuel delivery to the engine for optimal performance and efficiency. When the sensor is not performing correctly, it can lead to issues with fuel delivery, potentially causing the engine to run too rich or too lean, which can result in poor fuel economy, rough idling, or even engine stalling.

OBDII Code P128B 2015 GMC Sierra - Fuel Rail Pressure Sensor 2 Internal Performance
P128B 2015 GMC Sierra Code - Fuel Rail Pressure Sensor 2 Internal Performance

Common Causes of P128B 2015 GMC Sierra

  1. Faulty fuel rail pressure sensor
  2. Wiring or connector issues
  3. Fuel pressure regulator malfunction
  4. Fuel pump problems
  5. Issues with the fuel system

Symptoms of P128B 2015 GMC Sierra

  1. Poor fuel economy
  2. Rough idling or engine misfires
  3. Loss of power or acceleration
  4. Check engine light illuminated
  5. Engine stalling or difficulty starting

How to Fix P128B 2015 GMC Sierra

  1. Diagnose the issue by using a scan tool to read the code and check the fuel rail pressure sensor's readings.
  2. Inspect the wiring and connectors for any damage or corrosion, repairing or replacing as needed.
  3. Test the fuel pressure regulator and fuel pump to ensure they are functioning correctly.
  4. Replace the fuel rail pressure sensor if it is determined to be faulty.
  5. Clear the code and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P128B 2015 GMC Sierra

The cost of repairing a Fuel Rail Pressure Sensor 2 internal performance issue in a 2015 GMC Sierra can vary depending on the extent of the problem and the cost of parts and labor in your area. On average, the parts for this repair can range from $100 to $200, while the labor costs can be anywhere from $100 to $300. Overall, you can expect to pay between $200 and $500 for this repair. Keep in mind that prices may vary, so it's recommended to get quotes from different auto repair shops for a more accurate estimate.

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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.

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