AutoCodes – GMC – P128F 2017 GMC Sierra

P128F 2017 GMC Sierra Code - Fuel Rail Pressure Sensors 1 and 2 Signals Message Counter Incorrect

Quick Answer

The fuel rail pressure sensor transmits fuel pressure and temperature information by serial data. Common causes include Faulty Fuel Rail Pressure Sensor, Fuel Rail Pressure Sensor harness is open or shorted, Fuel Rail Pressure Sensor circuit poor electrical connection. 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: P128F 2017 GMC Sierra indicates Fuel Rail Pressure Sensors 1 and 2 Signals Message Counter Incorrect.
Common causes: Common causes include Faulty Fuel Rail Pressure Sensor, Fuel Rail Pressure Sensor harness is open or shorted, Fuel Rail Pressure Sensor circuit poor electrical connection.
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 300

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 Sep 27, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P128F 2017 GMC Sierra Description

The fuel rail pressure sensor transmits fuel pressure and temperature information by serial data. The fuel rail pressure sensor internal microprocessor allows 4 separate sensor outputs from one 3 wire sensor. The Engine Control Module (ECM) supplies the fuel rail pressure sensor with a 5 V reference circuit, a low reference circuit, and an asynchronous signal/serial data circuit. The asynchronous signal means communication is only going from the fuel rail pressure sensor to the ECM. The ECM decodes the serial data signal into separate voltages which are displayed on a scan tool as the voltage inputs from the Fuel Temperature Sensor, Fuel Rail Pressure Sensor and Fuel Rail Pressure Sensor 2.

OBDII Code P128F 2017 GMC Sierra - Fuel Rail Pressure Sensors 1 and 2 Signals Message Counter Incorrect - AutoCodes.com — P128F 2017 GMC Sierra Code - Fuel Rail Pressure Sensors 1 and 2 Signals Message Counter Incorrect

What does this mean?

What are the Possible Causes of the DTC P128F 2017 GMC Sierra?

Faulty Fuel Rail Pressure Sensor
Fuel Rail Pressure Sensor harness is open or shorted
Fuel Rail Pressure Sensor circuit poor electrical connection

How to Fix the DTC P128F 2017 GMC Sierra?

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 P128F 2017 GMC Sierra 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 P128F 2017 GMC Sierra code?

Need more information on how to fix the P128F 2017 GMC Sierra code? Get Access to Factory Service Manuals

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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 P128F 2017 GMC Sierra Code

1. What does the OBDII code P128F mean on a 2017 GMC Sierra?

P128F indicates an issue with the Fuel Rail Pressure Sensors 1 and 2, where the signals or message counters from the sensors are inconsistent or incorrect.

2. What are the common symptoms of code P128F in a 2017 GMC Sierra?

Symptoms may include reduced engine performance, poor fuel efficiency, difficulty starting, or the Check Engine Light being illuminated.

3. What causes the P128F code to appear on a GMC Sierra?

Possible causes include faulty fuel rail pressure sensors, wiring or connection issues, a malfunctioning fuel pump, or a problem with the engine control module (ECM).

4. Can a faulty fuel pump cause the P128F code?

Yes, a malfunctioning fuel pump can lead to fluctuating fuel pressure, which may trigger the P128F code.

5. How do you diagnose a P128F code on a 2017 GMC Sierra?

Diagnosis involves checking the fuel rail pressure sensors, inspecting the wiring and connectors, and using a scan tool to monitor sensor signals and fuel pressure readings.

6. Can driving with a P128F code damage my 2017 GMC Sierra?

Driving with this code may cause poor performance and could lead to engine damage if the fuel pressure is not properly regulated over time.

7. How do you fix the P128F code on a GMC Sierra?

Repairs may include replacing the faulty fuel rail pressure sensors, repairing damaged wiring or connectors, or addressing issues with the fuel pump or ECM.

8. How much does it cost to fix the P128F code?

Repair costs can vary but typically range from $200 to $500 depending on whether the issue is with the sensors, wiring, or fuel system components.

9. Can a software update fix the P128F code on a 2017 GMC Sierra?

In some cases, an ECM software update from the dealership may resolve the issue if it's caused by a programming error.

10. How can I prevent the P128F code from returning?

Regular maintenance, including inspecting fuel system components and ensuring proper electrical connections, can help prevent this code from reoccurring.