AutoCodes – GMC – P127C GMC

P127C GMC Code - Fuel Rail Pressure Sensor 2 Circuit Low Voltage

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 Sensor 2, Fuel Rail Pressure Sensor 2 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: P127C GMC indicates Fuel Rail Pressure Sensor 2 Circuit Low Voltage.
Common causes: Common causes include Low or no fuel, Faulty Fuel Rail Pressure Sensor 2, Fuel Rail Pressure Sensor 2 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 3,298

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on May 30, 2022

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P127C GMC 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 signal is less than a predefined threshold for greater than 1s.

OBDII Code P127C GMC - Fuel Rail Pressure Sensor 2 Circuit Low Voltage - AutoCodes.com — P127C GMC Code - Fuel Rail Pressure Sensor 2 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P127C GMC?

Low or no fuel
Faulty Fuel Rail Pressure Sensor 2
Fuel Rail Pressure Sensor 2 harness is open or shorted
Fuel Rail Pressure Sensor 2 circuit poor electrical connection
Faulty Fuel Pump

How to Fix the DTC P127C GMC?

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 does this mean?

Code Tech Notes

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P127C GMC 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 P127C GMC code?

Need more information on how to fix the P127C GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

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Information for Specific GMC Models

P127C 2014 GMC Sierra — Fuel Rail Pressure Sensor 2 Circuit Low Voltage
P127C 2015 GMC Sierra — Fuel Rail Pressure Sensor 2 Circuit Low Voltage
P127C 2016 GMC Sierra — Fuel Rail Pressure Sensor 2 Circuit Low Voltage
P127C 2017 GMC Sierra — Fuel Rail Pressure Sensor 2 Circuit Low Voltage
P127C 2018 GMC Sierra — Fuel Rail Pressure Sensor 2 Circuit Low Voltage

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 P127C GMC Code

1. What are the common symptoms of OBDII code P127C GMC?

The common symptoms of code P127C GMC include poor engine performance, decreased fuel efficiency, rough idling, and potential stalling.

2. What are the possible causes of OBDII code P127C GMC?

Possible causes of code P127C GMC include a faulty fuel rail pressure sensor, wiring issues, low fuel pressure, or a problem with the fuel pump.

3. How can I diagnose the issue related to OBDII code P127C GMC?

To diagnose the issue related to code P127C GMC, you can use a diagnostic scanner to read the code and perform a thorough inspection of the fuel rail pressure sensor and its wiring.

4. Can I continue driving my vehicle with OBDII code P127C GMC?

It is not recommended to continue driving your vehicle with code P127C GMC, as it can lead to further damage to the engine and components. It's best to address the issue promptly.

5. How can I repair OBDII code P127C GMC?

To repair code P127C GMC, you may need to replace the fuel rail pressure sensor, repair any damaged wiring, or address any issues with the fuel system causing low voltage.

6. Will resetting the OBDII code P127C GMC make the issue go away?

Resetting the code may temporarily clear the warning light, but if the underlying issue causing code P127C GMC is not addressed, the problem will likely reoccur.

7. Are there any DIY tips for troubleshooting OBDII code P127C GMC?

While basic troubleshooting like checking for loose connections or damaged wires can be done DIY, it's recommended to seek professional help for a thorough diagnosis and repair.

8. How much does it cost to fix OBDII code P127C GMC?

The cost of fixing code P127C GMC can vary depending on the specific issue causing the fault. Replacing the fuel rail pressure sensor or addressing wiring problems can range from a few hundred to over a thousand dollars.

9. Can a clogged fuel filter trigger OBDII code P127C GMC?

A clogged fuel filter can potentially lead to low fuel pressure, which may trigger code P127C GMC. It's important to check and replace the fuel filter if necessary as part of the diagnostic process.

10. Is OBDII code P127C GMC a serious issue?

Code P127C GMC should be taken seriously as it can affect the performance and reliability of your vehicle. Ignoring the issue may lead to more severe problems over time.