Engine-CodesGMC – P129C 2016 GMC Sierra

P129C 2016 GMC Sierra Code - Fuel Pump Driver Control Module System Voltage High

Quick Answer

The P129C diagnostic trouble code (DTC) for a 2016 GMC Sierra indicates a problem with the Fuel Pump Driver Control Module System Voltage being too high. Common causes include Faulty fuel pump driver control module, Damaged wiring or connectors related to the control module, Voltage regulator issues in the vehicle's electrical system. 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
P129C 2016 GMC Sierra indicates Fuel Pump Driver Control Module System Voltage High.
Common causes
Common causes include Faulty fuel pump driver control module, Damaged wiring or connectors related to the control module, Voltage regulator issues in the vehicle's electrical system.
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.
Table of contents Created and updated by William Orellana on Sep 10, 2024
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Code P129C 2016 GMC Sierra Description

The P129C diagnostic trouble code (DTC) for a 2016 GMC Sierra indicates a problem with the Fuel Pump Driver Control Module System Voltage being too high. The fuel pump driver control module is a crucial component of the vehicle's fuel system, responsible for controlling the fuel pump operation. When the system voltage is detected as being too high, it can lead to a range of issues that can affect the vehicle's performance and overall operation.

OBDII Code P129C 2016 GMC Sierra - Fuel Pump Driver Control Module System Voltage High
P129C 2016 GMC Sierra Code - Fuel Pump Driver Control Module System Voltage High

Common Causes of P129C 2016 GMC Sierra

  1. Faulty fuel pump driver control module
  2. Damaged wiring or connectors related to the control module
  3. Voltage regulator issues in the vehicle's electrical system
  4. Battery or alternator problems causing voltage spikes
  5. Water or corrosion affecting the control module

Symptoms of P129C 2016 GMC Sierra

  1. Engine stalling or hesitation during acceleration
  2. Rough idling or misfiring
  3. Difficulty starting the engine
  4. Decreased fuel efficiency
  5. Check Engine light illuminated on the dashboard

How to Fix P129C 2016 GMC Sierra

  1. Diagnose the root cause of the high voltage issue using a diagnostic scanner and multimeter.
  2. Inspect the fuel pump driver control module, wiring, and connectors for any signs of damage or corrosion.
  3. Replace the faulty fuel pump driver control module if necessary.
  4. Repair or replace any damaged wiring or connectors related to the control module.
  5. Test the vehicle to ensure proper fuel pump operation and system voltage levels.

Cost to Fix P129C 2016 GMC Sierra

The typical repair costs for addressing a P129C code can vary depending on the specific cause of the issue and the extent of the repairs needed. In general, replacing a faulty fuel pump driver control module can cost between $200 and $500, including parts and labor. However, additional costs may be incurred if there are wiring repairs or other related issues that need to be addressed.

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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 P129C 2016 GMC Sierra Code

1. What does the OBDII code P129C mean on a 2016 GMC Sierra?

P129C indicates that the Fuel Pump Driver Control Module has detected a high system voltage, which can affect fuel delivery and vehicle performance.

2. What are the common symptoms of code P129C in a 2016 GMC Sierra?

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

3. What causes the P129C code to appear?

Common causes include a failing Fuel Pump Driver Control Module, a faulty alternator, wiring issues (such as corroded or damaged connections), or a malfunctioning battery.

4. Can I drive my 2016 GMC Sierra with a P129C code?

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

5. How is the P129C code diagnosed?

A mechanic will typically use a scan tool to verify the code, inspect wiring and connections, test the Fuel Pump Driver Control Module, and measure system voltage levels.

6. What repairs can fix the P129C code in a 2016 GMC Sierra?

Repairs may include replacing the Fuel Pump Driver Control Module, repairing or replacing damaged wiring, or addressing alternator or battery issues.

7. How much does it cost to fix the P129C code?

Repair costs vary depending on the root cause but can range from $150 to $700, with Fuel Pump Driver Control Module replacement being one of the more expensive fixes.

8. Can a weak battery trigger the P129C code?

Yes, a weak or overcharging battery can cause voltage irregularities that trigger this code.

9. Is the P129C code related to other fuel system codes?

Yes, it may be related to other codes involving the fuel system or voltage, so a full diagnostic scan is recommended.

10. How can I prevent the P129C code from recurring?

Regular maintenance, including checking the battery, alternator, and fuel system components for proper function, can help prevent this code.

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