U0118 Code: Meaning, Symptoms, Causes & Fix

Overview

Symptoms

• hard starting
• engine may stall at idle
• hesitation under acceleration

Common causes

• CAN bus wiring fault affecting lost communication with fuel additive control module
• Network termination or gateway fault
• Connector pin damage/corrosion or harness stress near related components

How to diagnose U0118

1. Confirm U0118 and capture freeze-frame data with a professional scan tool.
2. Inspect wiring, connectors, and grounds related to lost communication with fuel additive control module for obvious defects.
3. Check CAN high/low integrity, network termination resistance, and module wake-up status.
4. Check for related DTCs to identify the root-cause chain before replacing parts.
5. After repair, clear codes and confirm readiness monitors complete without recurrence.

Severity of code U0118

Moderate: This code is moderate severity: the vehicle may still operate, but fault progression can increase repair cost over time.

Can you drive with U0118?

Most vehicles can be driven short-term with U0118, but postpone heavy load/highway driving until repaired.

If the warning lamp is flashing or drivability/safety is affected, avoid driving and diagnose immediately.

How to fix it (step-by-step)

1. Repair obvious wiring/connector faults first to prevent repeat parts replacement.
2. Address the root fault mode (communication) in the lost communication with fuel additive control module circuit/system.
3. Apply the required relearn/adaptation procedure if specified by service information.
4. Road-test and verify U0118 remains cleared under the conditions that originally set the code.

Fix options

• Stabilize voltage supply and module grounds.
• Repair CAN high/low wiring or termination issue.
• Clear DTCs and verify with live data and completed drive cycle.

Typical repair cost

$220-$1100

Common mistakes when diagnosing U0118

• Replacing parts without verifying voltage, ground, and signal integrity first.
• Ignoring related stored/pending codes that indicate upstream faults.
• Skipping post-repair verification drive cycle and readiness checks.

U0118 in common vehicles

U0118 appears across makes such as Ford, Toyota, Honda, Chevrolet. Failure patterns differ by platform: wiring routes, software calibration, and component supplier revisions can change root cause.

Frequently asked questions

What causes U0118?

U0118 is commonly set by communication faults affecting lost communication with fuel additive control module.

How much does it cost to fix U0118?

For U0118, repair costs are typically $220-$1100 depending on exact root cause, labor rates, and part quality.

Can I clear U0118 without repair?

You can clear U0118 temporarily, but the code usually returns until the underlying fault is corrected.

Helpful tools

• Estimate repair cost
• Decode your VIN
• Calculate fuel cost