FAULTBASE
Error CodesASKCars
© 2025 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
Home/Cars/Honda/Accord/10th Generation (2018-2022)/how to fix Honda Accord 10th Generation (2018-2022) U0401 code

how to fix Honda Accord 10th Generation (2018-2022) U0401 code

Honda Accord 10th Generation (2018-2022)

Error Codes
Severity: highDifficulty: mediumError Code: U04012-4 hours
3 min read
550 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix U0401 electrical communication issue in Honda Accord 10th Generation (2018-2022). Step-by-step guide with diagnostic procedures and repair instructions.

Error Code
U0401
Affected Component
Electrical
Estimated Time
2-4 hours

Safety Warnings

  • ⚠Disconnect the battery before working on electrical systems to prevent shocks or shorts.
  • ⚠Allow the engine to cool before handling any components near the engine bay.

Symptoms

  • •Check engine light illuminated
  • •Erratic engine performance
  • •Transmission shifting issues
  • •Inconsistent fuel economy
  • •Warning messages on the dashboard
  • •Difficulty in starting the engine

Diagnostic Steps

  1. 1Scan for error codes using an OBD-II scanner to confirm the presence of U0401 and any related codes.
  2. 2Inspect the vehicle's wiring harness and connectors related to the ECM for damage or corrosion.
  3. 3Check the ECM for proper grounding and power supply.
  4. 4Verify the software version of the ECM and check for any available updates from the manufacturer.
  5. 5Test the communication lines between the ECM and other modules using a multimeter.
  6. 6Clear the U0401 code and perform a test drive to see if the code reappears.

Solution

Solution

1. Preparation

  • Gather necessary tools and parts.
  • Disconnect the negative battery terminal to prevent electrical shorts.
  • Ensure the vehicle is in a stable position with the ignition off.

2. Inspect Wiring and Connectors

  • Tools Required: Visual inspection tools, flashlight.
    • Examine the wiring harness connected to the ECM for wear, corrosion, or broken wires.
    • Check the connectors for proper seating and any signs of damage.

3. Test ECM Power and Ground

  • Tools Required: Multimeter.
    • Reconnect the battery and turn the ignition to the "ON" position without starting the engine.
    • Use a multimeter to test for voltage at the ECM power supply pins (should be around 12V).
    • Check ground pins for continuity to the chassis ground.

4. Update ECM Software

  • Tools Required: OBD-II scanner with programming capability.
    • If the ECM is not up-to-date, connect the OBD-II scanner and follow the manufacturer’s instructions to update the software.

5. Repair or Replace Faulty Components

  • If any wiring or connectors are damaged, repair them by splicing or replacing as necessary.
  • If the ECM is determined to be faulty after testing, replace it with a new or refurbished unit.
    • Follow manufacturer specifications for installation and ensure all connections are secure.

6. Reassemble and Clear Codes

  • Reconnect all harnesses and connectors securely.
  • Reconnect the negative battery terminal.
  • Use the OBD-II scanner to clear the U0401 code and any other related codes.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •OBD-II scanner
  • •Multimeter
  • •Visual inspection tools
  • •Socket set

Parts Required

  • •Wiring harness (if damaged)
  • •ECM (if defective)

Additional Information

Error Code
U0401
Affected Component
Electrical
Estimated Time
2-4 hours
Difficulty
medium
Severity
high
Tools Required
4 items
Parts Required
2 items

Related Faults

  1. my Honda Accord displays a dashboard warning light what does it mean

    Learn how to diagnose and fix dashboard warning lights on Honda Accord. Step-by-step guide with diagnostic procedures and repair instructions.

    Electrical5 symptoms

  2. what could cause my Honda Accord to have a delayed steering response?

    Learn how to diagnose and fix delayed steering response in Honda Accord. Step-by-step guide with diagnostic procedures and repair instructions.

    Steering5 symptoms

  3. my Honda Accord keeps showing the seatbelt warning light when buckled what should I do

    Learn how to diagnose and fix the seatbelt warning light issue in Honda Accord. Step-by-step guide with diagnostic procedures and repair instructions.

    Electrical5 symptoms

  4. how to fix my Honda Accord that has a hard brake pedal

    Learn how to diagnose and fix a hard brake pedal issue in Honda Accord. Step-by-step guide with diagnostic procedures and repair instructions.

    Brakes5 symptoms

  5. my Honda Accord transmission is slipping when going uphill what should I do

    Learn how to diagnose and fix transmission slipping issues in Honda Accord. Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

    Transmission6 symptoms

  6. my Honda Accord squeals when I start it what could that mean

    Learn how to diagnose and fix a squealing noise in your Honda Accord. Step-by-step guide with diagnostic procedures and repair instructions.

    Engine5 symptoms

Share this solution

Comments

Sign in to share your thoughts

Sign In

No comments yet

Be the first to share your thoughts

Back to Generation