AutoCodes – Chevrolet – P128B 2016 Chevrolet Silverado

P128B 2016 Chevrolet Silverado Code - Fuel Rail Pressure Sensor 2 Internal Performance

Quick Answer

The Engine Control Module (ECM) uses the Fuel Rail Pressure (FRP) sensor to constantly adjust the high-pressure fuel pump's feed rate so that the ideal pressure is permanently maintained in the high-pressure section (between the high-pressure fuel pump and the injectors) by means of closed-loop control. Common causes include Low or no fuel, Faulty Fuel Rail Pressure (FRP) Sensor, Fuel Rail Pressure 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: P128B 2016 Chevrolet Silverado indicates Fuel Rail Pressure Sensor 2 Internal Performance.
Common causes: Common causes include Low or no fuel, Faulty Fuel Rail Pressure (FRP) Sensor, Fuel Rail Pressure 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 286

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 May 30, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P128B 2016 Chevrolet Silverado Description

The Engine Control Module (ECM) uses the Fuel Rail Pressure (FRP) sensor to constantly adjust the high-pressure fuel pump's feed rate so that the ideal pressure is permanently maintained in the high-pressure section (between the high-pressure fuel pump and the injectors) by means of closed-loop control. The fuel rail pressure sensor transmits fuel pressure and temperature information via serial data to the ECM. When the fuel pressure is high, the signal voltage is high. When the fuel pressure is low, the signal voltage is low. The ECM controls the fuel pressure regulator, which regulates high-pressure fuel that goes to the fuel injector rails and the injectors. The Diagnostic Trouble Code (DTC) will be set if the Fuel Rail Pressure Sensor 2 is greater than a predefined threshold for greater than 2.6 s

OBDII Code P128B 2016 Chevrolet Silverado - Fuel Rail Pressure Sensor 2 Internal Performance - AutoCodes.com — P128B 2016 Chevrolet Silverado Code - Fuel Rail Pressure Sensor 2 Internal Performance

What does this mean?

What are the Possible Causes of the DTC P128B 2016 Chevrolet Silverado?

Low or no fuel
Faulty Fuel Rail Pressure (FRP) Sensor
Fuel Rail Pressure harness is open or shorted
Fuel Rail Pressure circuit poor electrical connection
Faulty Fuel Pump

How to Fix the DTC P128B 2016 Chevrolet Silverado?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P128B 2016 Chevrolet Silverado 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 P128B 2016 Chevrolet Silverado code?

Need more information on how to fix the P128B 2016 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

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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.

Frequently Asked Questions about P128B 2016 Chevrolet Silverado Code

What does the OBDII code P128B mean on a 2016 Chevrolet Silverado?

P128B indicates an issue with the Fuel Rail Pressure Sensor 2's internal performance, typically related to inaccurate or faulty pressure readings.

What are the symptoms of code P128B on a 2016 Chevrolet Silverado?

Symptoms may include reduced engine performance, poor fuel efficiency, difficulty starting, or the check engine light being illuminated.

What causes the P128B code to appear on a 2016 Chevrolet Silverado?

Common causes include a faulty fuel rail pressure sensor, wiring issues, a malfunctioning fuel pump, or a problem with the vehicleâ€™s ECM.

How do I diagnose the P128B code on my Silverado?

Start by using an OBDII scanner to confirm the code, inspect the fuel rail pressure sensor and its wiring for damage, and test the fuel system's pressure readings.

Can I drive my Silverado with a P128B code?

Driving with this code is not recommended, as it may lead to reduced engine performance or further damage to the fuel system.

How do I fix the P128B code on a 2016 Chevrolet Silverado?

Repairs may involve replacing the fuel rail pressure sensor, repairing damaged wiring, or addressing fuel system issues such as a failing pump.

How much does it cost to fix the P128B code on a Silverado?

Repair costs vary but may range from $150 to $400, depending on whether the issue is with the sensor, wiring, or other fuel system components.

Can a dirty fuel filter cause the P128B code?

While uncommon, a clogged or dirty fuel filter can restrict fuel flow, potentially leading to fuel pressure irregularities and triggering this code.

Does a software update fix the P128B code?

In some cases, an ECM software update from the dealership may resolve miscommunication issues causing the code, but this depends on the specific vehicle and problem.

How can I prevent the P128B code from recurring?

Regular maintenance, such as replacing the fuel filter and inspecting fuel system components, can help prevent fuel pressure sensor issues and related codes.