AutoCodes – GMC – P128C 2017 GMC Sierra

P128C 2017 GMC Sierra Code - Fuel Rail Temperature Sensor 1 Signal 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 Temperature Sensor 1, Fuel Rail Temperature Sensor 1 harness is open or shorted, Fuel Rail Temperature Sensor 1 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: P128C 2017 GMC Sierra indicates Fuel Rail Temperature Sensor 1 Signal Message Counter Incorrect.
Common causes: Common causes include Faulty Fuel Rail Temperature Sensor 1, Fuel Rail Temperature Sensor 1 harness is open or shorted, Fuel Rail Temperature Sensor 1 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 266

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 26, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P128C 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 P128C 2017 GMC Sierra - Fuel Rail Temperature Sensor 1 Signal Message Counter Incorrect - AutoCodes.com — P128C 2017 GMC Sierra Code - Fuel Rail Temperature Sensor 1 Signal Message Counter Incorrect

What does this mean?

What are the Possible Causes of the DTC P128C 2017 GMC Sierra?

Faulty Fuel Rail Temperature Sensor 1
Fuel Rail Temperature Sensor 1 harness is open or shorted
Fuel Rail Temperature Sensor 1 circuit poor electrical connection

How to Fix the DTC P128C 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 P128C 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 P128C 2017 GMC Sierra 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 P128C 2017 GMC Sierra Code

1. What does the OBDII code P128C mean on a 2017 GMC Sierra?

P128C indicates that the Fuel Rail Temperature Sensor 1 is sending an incorrect signal message counter to the engine control module (ECM).

2. What are the common symptoms of code P128C?

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

3. What causes the P128C code to appear?

Common causes include a faulty fuel rail temperature sensor, damaged wiring or connectors, or a malfunctioning ECM.

4. Can I drive my 2017 GMC Sierra with the P128C code?

While it may be possible to drive, itâ€™s not recommended as it could lead to further engine performance issues or potential damage.

5. How do you diagnose the P128C code on a 2017 GMC Sierra?

Diagnosis involves using a scan tool to confirm the code, inspecting the wiring and connectors for damage, and testing the fuel rail temperature sensor for proper functionality.

6. How do you fix the P128C code?

Repairs include replacing the faulty fuel rail temperature sensor, repairing or replacing damaged wiring or connectors, or reprogramming the ECM if necessary.

7. How much does it cost to fix the P128C code on a GMC Sierra?

Costs can vary, but replacing the fuel rail temperature sensor typically ranges from $150 to $300, including parts and labor.

8. Can a bad fuel rail temperature sensor cause other problems?

Yes, a faulty sensor can lead to incorrect fuel delivery, reduced engine efficiency, and potential long-term engine damage.

9. What tools are needed to fix the P128C code?

Common tools include a scan tool, multimeter for testing wiring, and basic hand tools for sensor replacement.

10. Is the P128C code covered under warranty for a 2017 GMC Sierra?

It depends on your vehicle's warranty status and coverage, but emissions-related components may be covered under the federal emissions warranty. Check with your dealer for details.