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Engine-Codes – Generic – U0109

U0109 Code - Lost Communication With Fuel Pump Control Module

Quick Answer

The U0109 diagnostic trouble code (DTC) indicates that the vehicle's control module has lost communication with the fuel pump control module. Common causes include Faulty fuel pump control module, Wiring or connection issues between the control module and fuel pump module, Corrosion or damage to the electrical connectors. 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 indicates Lost Communication With Fuel Pump Control Module.
Common causes
Common causes include Faulty fuel pump control module, Wiring or connection issues between the control module and fuel pump module, Corrosion or damage to the electrical connectors.
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 Aug 19, 2024
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Code U0109 Description

The U0109 diagnostic trouble code (DTC) indicates that the vehicle's control module has lost communication with the fuel pump control module. This can lead to various issues with the fuel pump operation, potentially affecting the vehicle's performance and fuel delivery system. 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 for optimal performance. When communication is lost between the control module and the fuel pump module, the fuel pump may not function properly, leading to engine stalling, poor acceleration, and other drivability issues.

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

Common Causes of U0109

  1. Faulty fuel pump control module
  2. Wiring or connection issues between the control module and fuel pump module
  3. Corrosion or damage to the electrical connectors
  4. Software or programming issues with the vehicle's control modules
  5. Electrical system issues such as a dead battery or alternator problems

Symptoms of U0109

  1. Engine stalling or rough idling
  2. Poor acceleration or loss of power
  3. Difficulty starting the engine
  4. Fuel pump not priming when the ignition is turned on
  5. Check engine light illuminated on the dashboard

How to Fix U0109

  1. Perform a visual inspection of the wiring and connectors between the control module and fuel pump module.
  2. Check for any corrosion or damage to the electrical connectors and repair or replace as needed.
  3. Test the fuel pump control module for proper operation and replace if faulty.
  4. Clear the DTC and reset the vehicle's computer system to see if the issue recurs.
  5. If the problem persists, further diagnostics may be required to pinpoint the exact cause of the communication loss.

Cost to Fix U0109

The cost of repairing a lost communication issue with the fuel pump control module can vary depending on the specific cause of the problem. In general, replacing a faulty fuel pump control module can cost anywhere from $200 to $500, including parts and labor. However, additional diagnosis and repair costs may apply if the issue is related to wiring or connection problems. It's recommended to consult with a trusted mechanic or dealership to get a more accurate estimate based on the make and model of your vehicle.

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Code U0109 Information for Specific Makes

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 Code

What does the OBDII code U0109 mean?

1. The U0109 code indicates a lost communication between the Powertrain Control Module (PCM) and the Fuel Pump Control Module (FPCM). 2.

What are the common symptoms of code U0109?

Symptoms may include engine stalling, failure to start, rough idling, poor fuel efficiency, or the fuel pump not running. 3.

What causes the U0109 code to appear?

Common causes include faulty wiring, damaged connectors, a defective Fuel Pump Control Module, or issues with the Powertrain Control Module. 4.

Can I drive my car with the U0109 code?

Driving with this code may not be safe if the engine stalls or the fuel pump fails. It's best to address the issue promptly. 5.

How do I diagnose the U0109 code?

Check the wiring and connectors for damage or corrosion, test the Fuel Pump Control Module, and ensure the PCM is functioning properly. 6.

Is a faulty Fuel Pump Control Module the only cause of code U0109?

No, other causes include communication circuit issues, software errors, or a malfunctioning PCM. 7.

How much does it cost to fix the U0109 code?

Repair costs vary but can range from $100 for wiring repairs to $500+ if the Fuel Pump Control Module needs replacement. 8.

Can a dead battery trigger code U0109?

Yes, a low-voltage or dead battery can disrupt communication between the modules and trigger this code. 9.

How do I reset the U0109 code?

The code can be reset with an OBDII scanner after repairing the underlying issue, but it may return if the problem persists. 10.

Does the U0109 code always mean the Fuel Pump Control Module needs replacement?

No, the module may not need replacement if the issue is with wiring, connectors, or the communication circuit.

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