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Engine-Codes – GMC – U0109 GMC

U0109 GMC Code - Lost Communication With Fuel Pump Control Module

Quick Answer

The U0109 diagnostic trouble code (DTC) for GMC vehicles indicates that there is a communication issue between the engine control module (ECM) and the fuel pump control module. Common causes include Faulty wiring or connectors, Defective fuel pump control module, Corrosion or damage to electrical connections. 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
U0109 GMC indicates Lost Communication With Fuel Pump Control Module .
Common causes
Common causes include Faulty wiring or connectors, Defective fuel pump control module, Corrosion or damage to electrical connections.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 08, 2024
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Code U0109 GMC Description

The U0109 diagnostic trouble code (DTC) for GMC vehicles indicates that there is a communication issue between the engine control module (ECM) and the fuel pump control module. This means that the ECM is not receiving the necessary information from the fuel pump control module to regulate the fuel pump's operation effectively. The fuel pump control module plays a crucial role in managing the fuel pump's performance, ensuring that the engine receives the right amount of fuel for optimal operation.

OBDII Code U0109 GMC - Lost Communication With Fuel Pump Control Module
U0109 GMC Code - Lost Communication With Fuel Pump Control Module

Common Causes of U0109 GMC

  1. Faulty wiring or connectors
  2. Defective fuel pump control module
  3. Corrosion or damage to electrical connections
  4. Software issues in the ECM or fuel pump control module
  5. Water damage or exposure to moisture in the control module area

Symptoms of U0109 GMC

  1. Engine stalling or hesitation during acceleration
  2. Rough idling or misfires
  3. Poor fuel economy
  4. Illumination of the check engine light
  5. Difficulty starting the vehicle

How to Fix U0109 GMC

  1. Perform a diagnostic scan to retrieve the trouble code and identify the specific cause of the communication issue.
  2. Inspect the wiring harness, connectors, and terminals for any signs of damage or corrosion. Repair or replace as needed.
  3. Check the fuel pump control module for any faults or malfunctions. Replace if necessary.
  4. Clear the DTC and perform a test drive to ensure that the communication between the ECM and fuel pump control module has been restored.
  5. Conduct a final scan to verify that the code has been successfully resolved and that the vehicle's performance has returned to normal.

Cost to Fix U0109 GMC

The typical repair costs for resolving the U0109 code can vary depending on the specific cause of the issue and the extent of the repairs needed. In general, the cost of parts such as a new fuel pump control module and labor for diagnosis and repair can range from $200 to $500 or more. It is essential to consider additional costs for diagnostic time and potential reprogramming of modules, which can increase the overall repair bill. As labor rates can vary, it is advisable to consult with local auto repair shops for a more accurate estimate based on your vehicle's make and model.

What does this mean?

Tech Notes for U0109 GMC

There is a factory service bulletin for the following GMC models:
2007-2010 GMC Sierra
2007-2010 GMC Yukon Models
2008-2010 GMC Sierra Hybrid
2008-2010 GMC Yukon Hybrid
GMC Factory Service Bulletin OBDII Code U0109

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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 U0109 GMC Code

1. What does the OBDII code U0109 GMC indicate?

The code U0109 GMC signifies a communication problem between the vehicle's engine control module (ECM) and the fuel pump control module.

2. What are common symptoms of the U0109 GMC code?

Common symptoms include issues with starting the vehicle, engine stalling, poor fuel efficiency, and sometimes the vehicle not starting at all.

3. What are potential causes of the U0109 GMC code?

Potential causes include a faulty fuel pump control module, damaged wiring or connectors in the communication network, software issues, or a malfunctioning ECM.

4. How can I diagnose the U0109 GMC code?

Diagnosing this code typically involves using a professional OBDII scanner to retrieve the code, checking for any associated codes, and performing a thorough inspection of the fuel pump control module and related wiring.

5. Can I still drive my vehicle with the U0109 GMC code?

It is generally not recommended to drive the vehicle when this code is present, as it can lead to potential safety hazards and further damage to the vehicle's components.

6. How can I repair the U0109 GMC code?

Repairing this code usually involves addressing the root cause, which may include replacing the fuel pump control module, repairing damaged wiring, or reprogramming the ECM.

7. Is it possible to reset the U0109 GMC code without repairs?

While clearing the code temporarily may be possible by using an OBDII scanner, it is essential to address the underlying issue to prevent the code from reappearing.

8. Are there any DIY tips for fixing the U0109 GMC code?

DIY tips may include checking for loose connections, inspecting the wiring harness for damage, and ensuring all components related to the fuel pump control module are securely in place.

9. Can a mechanic help with the U0109 GMC code repair?

Yes, a qualified mechanic or automotive technician can help diagnose and repair the U0109 GMC code using their expertise and specialized tools.

10. How much does it cost to fix the U0109 GMC code?

The cost of fixing the U0109 GMC code can vary depending on the extent of the issue, the parts needed for repair, and the labor rates of the service provider. It's advisable to get estimates from different repair shops.

Discuss the causes and fixes for U0109 GMC OBDII Code

Submit a New Comment

  • my 2014 acadia has code UO 109 but runs great. Can I expect fuel pump failure?

    Reply to Comment

  • No, more like a Fuel Pump Control Module problem. I suggest clearing the code first and if possible inspect the Fuel Pump Control Module connector, make sure none of the pins are not burnt out or black

    Reply to Comment