What causes B1055 on a Honda?

Faulty multiplex integrated control unit (MICU) Open or short in the MICU harness Poor connection in the MICU circuit Faulty relay control module Corroded or loose pins on the data link

How do I fix B1055 on a Honda?

Confirm the code and check every module for related faults Inspect the data link connectors at both ends for corrosion and loose pins Test the data link wiring for opens and shorts Repair damaged wiring or connectors before replacing a module Replace the relay control module that fails testing Clear the code and retest

B1055 The relay control module lost communication with the multiplex integrated control unit

Q: What does B1055 mean on a Honda?

B1055. The relay control module lost communication with the multiplex integrated control unit. Circuits that rely on that link may stop working. Applies to Honda and Acura models that use this code.

Category: Network Communications
Severity: Check Engine Light
Applies to: Honda and Acura models that use this code

What does B1055 mean on a Honda?

B1055. The relay control module lost communication with the multiplex integrated control unit. Circuits that rely on that link may stop working. This Honda-enhanced code applies to Honda and Acura models that use this code.

Common causes of B1055

Faulty multiplex integrated control unit (MICU)
Open or short in the MICU harness
Poor connection in the MICU circuit
Faulty relay control module
Corroded or loose pins on the data link

How to fix B1055

Confirm the code and check every module for related faults
Inspect the data link connectors at both ends for corrosion and loose pins
Test the data link wiring for opens and shorts
Repair damaged wiring or connectors before replacing a module
Replace the relay control module that fails testing
Clear the code and retest

Sources and review

Last updated 2026-10-10.