AutoCodes – Hummer – U0109 Hummer

U0109 Hummer Code - Lost Communication With Fuel Pump Control Module

Quick Answer

Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Common causes include Faulty Fuel Pump Control Module, Fuel Pump Control Module harness is open or shorted, Fuel Pump Control Module 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: U0109 Hummer indicates Lost Communication With Fuel Pump Control Module .
Common causes: Common causes include Faulty Fuel Pump Control Module, Fuel Pump Control Module harness is open or shorted, Fuel Pump Control Module 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 6,448

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 Jun 29, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code U0109 Hummer Description

Modules connected to the high speed General Motor Local Area Network (GMLAN) serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver module as an availability indication of the transmitter module. The supervision time-out period is 250 ms. Each message contains the identification number of the transmitter module.

OBDII Code U0109 Hummer - Lost Communication With Fuel Pump Control Module - AutoCodes.com — U0109 Hummer Code - Lost Communication With Fuel Pump Control Module

What does this mean?

What are the Possible Causes of the DTC U0109 Hummer?

Faulty Fuel Pump Control Module
Fuel Pump Control Module harness is open or shorted
Fuel Pump Control Module circuit poor electrical connection

How to Fix the DTC U0109 Hummer?

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

There is a factory service bulletin for the 2008-2009 HUMMER H2:
2008-2009 HUMMER H2 Factory Service Bulletin OBDII Code U0109

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the U0109 Hummer 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 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?

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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 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.