AutoCodes – GMC – P128F 2018 GMC Sierra

P128F 2018 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 2018 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 236

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 2018 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 2018 GMC Sierra - Fuel Rail Pressure Sensors 1 and 2 Signals Message Counter Incorrect - AutoCodes.com — P128F 2018 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 2018 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 2018 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 2018 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 2018 GMC Sierra code?

Need more information on how to fix the P128F 2018 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 2018 GMC Sierra Code

1. What are the common symptoms of OBDII code P128F in a 2018 GMC Sierra?

- Common symptoms include rough idling, decreased fuel efficiency, and potentially stalling while driving.

2. What causes the OBDII code P128F related to Fuel Rail Pressure Sensors 1 and 2 Signals Message Counter Incorrect in a 2018 GMC Sierra?

- This code is typically triggered by issues such as faulty fuel rail pressure sensors, wiring problems, or issues with the engine control module.

3. How can I diagnose the OBDII code P128F in my 2018 GMC Sierra?

- Diagnosis involves using an OBDII scanner to read the code, checking the fuel rail pressure sensor readings, inspecting the wiring harness for damage, and testing the sensor's functionality.

4. Can I continue driving my 2018 GMC Sierra with the OBDII code P128F present?

- It is not recommended to continue driving with this code present, as it can lead to potential engine performance issues and further damage if left unresolved.

5. How can I repair the OBDII code P128F in my 2018 GMC Sierra?

- Repair options may include replacing the faulty fuel rail pressure sensors, repairing any damaged wiring, or reprogramming the engine control module.

6. Is it safe to reset the OBDII code P128F in my 2018 GMC Sierra using an OBDII scanner?

- While resetting the code can temporarily clear it, it is important to address the underlying issue causing the code to prevent future problems and ensure proper vehicle operation.

7. Are there any preventative maintenance steps I can take to avoid the OBDII code P128F in my 2018 GMC Sierra?

- Regularly inspecting and maintaining the fuel system components, such as fuel rail pressure sensors, can help prevent issues that lead to this code.

8. Can a DIY enthusiast with automotive experience repair the OBDII code P128F in a 2018 GMC Sierra?

- Depending on the skill level and tools available, some DIY enthusiasts may be able to diagnose and repair this code, but professional assistance is recommended for complex issues.

9. Will replacing the fuel rail pressure sensors fix the OBDII code P128F in my 2018 GMC Sierra?

- In many cases, replacing the faulty fuel rail pressure sensors can resolve the P128F code, but it is important to ensure there are no underlying wiring or ECM issues causing the problem.

10. How long does it typically take to repair the OBDII code P128F in a 2018 GMC Sierra?

- The repair time can vary based on the specific issue causing the code, but it may take a few hours to a day to diagnose, repair, and test the system to ensure the code does not return.