Engine-CodesGeneric – U0118

U0118 Code - Lost Communication With Fuel Additive Control Module

Quick Answer

The U0118 code indicates that the vehicle's onboard computer has lost communication with the Fuel Additive Control Module. Common causes include Faulty Wiring: A damaged or loose wiring harness connecting the Fuel Additive Control Module to the onboard computer can interrupt communication, Blown Fuse: A blown fuse related to the Fuel Additive Control Module can prevent proper communication between the module and the onboard computer, Malfunctioning Module: The Fuel Additive Control Module itself may be malfunctioning, causing communication issues with the onboard computer. 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
U0118 indicates Lost Communication With Fuel Additive Control Module.
Common causes
Common causes include Faulty Wiring: A damaged or loose wiring harness connecting the Fuel Additive Control Module to the onboard computer can interrupt communication, Blown Fuse: A blown fuse related to the Fuel Additive Control Module can prevent proper communication between the module and the onboard computer, Malfunctioning Module: The Fuel Additive Control Module itself may be malfunctioning, causing communication issues with the onboard computer.
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 11, 2024
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Code U0118 Description

The U0118 code indicates that the vehicle's onboard computer has lost communication with the Fuel Additive Control Module. This module is responsible for managing the fuel additive system, which is crucial for reducing emissions and improving fuel efficiency. When communication is lost with this module, it can lead to various issues that affect the vehicle's performance and emissions control system.

OBDII Code U0118 - Lost Communication With Fuel Additive Control Module
U0118 Code - Lost Communication With Fuel Additive Control Module

Common Causes of U0118

  1. Faulty Wiring: A damaged or loose wiring harness connecting the Fuel Additive Control Module to the onboard computer can interrupt communication.
  2. Blown Fuse: A blown fuse related to the Fuel Additive Control Module can prevent proper communication between the module and the onboard computer.
  3. Malfunctioning Module: The Fuel Additive Control Module itself may be malfunctioning, causing communication issues with the onboard computer.
  4. Corrosion: Corrosion on the electrical connectors or terminals can also disrupt communication between the module and the computer.
  5. Software Issues: Software glitches or programming errors within the vehicle's computer system can also lead to the U0118 code.

Symptoms of U0118

  1. Check Engine Light: The most common symptom associated with the U0118 code is the illumination of the check engine light on the dashboard.
  2. Reduced Fuel Efficiency: If the Fuel Additive Control Module is not functioning correctly, it can lead to decreased fuel efficiency as the proper amount of fuel additive may not be injected into the fuel system.
  3. Emissions Issues: A malfunctioning Fuel Additive Control Module can result in increased emissions, potentially causing the vehicle to fail emissions tests.
  4. Engine Performance Problems: In severe cases, loss of communication with the Fuel Additive Control Module can impact the engine's performance, leading to rough idling, misfiring, or stalling.

How to Fix U0118

  1. Diagnose the Issue: Use a diagnostic scanner to retrieve the trouble codes and pinpoint the exact cause of the communication loss with the Fuel Additive Control Module.
  2. Check Wiring and Connections: Inspect the wiring harness and connectors for any damage, corrosion, or loose connections. Repair or replace as needed.
  3. Test Fuses: Check the fuses related to the Fuel Additive Control Module and replace any blown fuses.
  4. Replace the Module: If the Fuel Additive Control Module is found to be faulty, it will need to be replaced with a new one.
  5. Clear Codes and Test: After completing the repairs, clear the trouble codes from the vehicle's computer system and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix U0118

The typical repair costs for addressing the U0118 code can vary depending on the exact cause of the issue and the cost of parts and labor. On average, the cost of diagnosing and repairing this issue can range from $200 to $500. This estimate includes the cost of parts such as a new Fuel Additive Control Module, wiring harness, and fuses, as well as labor costs for diagnosis and repair. It's important to note that specific diagnosis 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, vehicle make and model, and engine type.

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Code U0118 Information for Specific Makes

  • U0118 Ford — Lost Communication With Fuel Additive Control Module
  • U0118 Lincoln — Lost Communication With Fuel Additive Control Module
  • U0118 Mercury — Lost Communication With Fuel Additive Control Module
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.

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