Engine-Codes.com
Engine-Codes – Hummer – U0109 Hummer

U0109 Hummer Code - Lost Communication With Fuel Pump Control Module

Quick Answer

The U0109 diagnostic trouble code (DTC) for Hummer vehicles indicates that there is a communication problem between the Engine Control Module (ECM) and the Fuel Pump Control Module. Common causes include Faulty wiring or connectors between the ECM and fuel pump control module, Malfunctioning fuel pump control module, ECM software glitch. 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 Hummer indicates Lost Communication With Fuel Pump Control Module .
Common causes
Common causes include Faulty wiring or connectors between the ECM and fuel pump control module, Malfunctioning fuel pump control module, ECM software glitch.
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 13, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code U0109 Hummer Description

The U0109 diagnostic trouble code (DTC) for Hummer vehicles indicates that there is a communication problem between the Engine Control Module (ECM) and the Fuel Pump Control Module. This means that the ECM is unable to receive or send data to the fuel pump control module, which can lead to issues with fuel delivery and overall engine performance. The fuel pump control module is responsible for regulating the fuel pump's operation, ensuring the correct amount of fuel is delivered to the engine at all times. When communication is lost between these two modules, it can result in poor fuel efficiency, rough idling, stalling, and even a no-start condition.

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

Common Causes of U0109 Hummer

  1. Faulty wiring or connectors between the ECM and fuel pump control module
  2. Malfunctioning fuel pump control module
  3. ECM software glitch
  4. Corrosion or damage to the communication lines
  5. Electrical interference from other components

Symptoms of U0109 Hummer

  1. Engine misfires or hesitation during acceleration
  2. Rough idling or stalling
  3. Decreased fuel efficiency
  4. Illuminated check engine light
  5. Difficulty starting the vehicle

How to Fix U0109 Hummer

  1. Begin by conducting a thorough visual inspection of the wiring and connectors between the ECM and fuel pump control module. Look for any signs of damage, corrosion, or loose connections.
  2. Use a diagnostic scan tool to check for any stored trouble codes and to attempt to establish communication between the two modules.
  3. If no visible issues are found, test the fuel pump control module and ECM for proper functionality. Replace any components that are found to be faulty.
  4. Clear the DTC from the vehicle's memory using the diagnostic scan tool and perform a test drive to ensure the issue has been resolved.
  5. If the problem persists, consult a professional technician for further diagnosis and repair.

Cost to Fix U0109 Hummer

The cost of repairing a U0109 DTC can vary depending on the specific cause of the issue. In general, the cost of parts for this repair can range from $100 to $500, with labor costs adding an additional $100 to $200. Keep in mind that diagnostic time and labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate based on your location and vehicle model.

What does this mean?

Tech Notes for U0109 Hummer

There is a factory service bulletin for the 2008-2009 HUMMER H2:

2008-2009 HUMMER H2 Factory Service Bulletin OBDII Code U0109

Need more information about the U0109 Hummer code?

Need more information on how to fix the U0109 Hummer code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the U0109 Hummer code diagnosed by a professional: Find a repair shop in your area

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 Hummer Code

1. What are the common symptoms of OBDII code U0109 (Lost Communication With Fuel Pump Control Module) in a Hummer?

- Common symptoms include issues with starting the vehicle, engine stalling, and the fuel pump not functioning properly.

2. What are some possible causes of OBDII code U0109 in a Hummer?

- Possible causes include a faulty fuel pump control module, damaged wiring or connectors, a malfunctioning powertrain control module (PCM), or software issues.

3. How can I diagnose OBDII code U0109 in my Hummer?

- Diagnosis typically involves using a diagnostic scanner to retrieve the trouble codes, checking the wiring and connectors for any visible damage, and testing the fuel pump control module for proper function.

4. Can I still drive my Hummer with OBDII code U0109 present?

- It is not recommended to drive the vehicle with this code present, as it can lead to potential safety hazards and further damage to the fuel system.

5. How can I repair OBDII code U0109 in my Hummer?

- Repair options include replacing the fuel pump control module, repairing any damaged wiring or connectors, updating the PCM software, or seeking assistance from a qualified mechanic.

6. Are there any DIY tips for troubleshooting OBDII code U0109 in my Hummer?

- DIY tips include checking the fuse related to the fuel pump control module, inspecting the wiring harness for any signs of wear or corrosion, and ensuring all connections are secure.

7. How much does it typically cost to fix OBDII code U0109 in a Hummer?

- The cost of repair can vary depending on the specific issue causing the code, but it may range from $200 to $600, including parts and labor.

8. Can a faulty fuel pump cause OBDII code U0109 to appear in a Hummer?

- While a faulty fuel pump itself may not directly trigger this code, communication issues with the fuel pump control module can lead to the appearance of OBDII code U0109.

9. How important is it to address OBDII code U0109 promptly in a Hummer?

- It is important to address this code promptly to prevent potential fuel system malfunctions, engine performance issues, and safety concerns while driving the vehicle.

10. Is OBDII code U0109 a common issue in Hummer vehicles?

- While not extremely common, OBDII code U0109 (Lost Communication With Fuel Pump Control Module) can occur in Hummer vehicles, particularly in older models or those with high mileage.

Discuss the causes and fixes for U0109 Hummer OBDII Code

Submit a New Comment

Code U0109 Hummer comments

No comments found for this page.