B1255 The combination switch control unit lost communication with the MICU
What does B1255 mean on a Honda?
B1255. The combination switch control unit lost communication with the MICU. Turn signal, wiper, and lighting inputs may stop reaching the body control unit. This Honda-enhanced code applies to Honda and Acura models that use this code.
Common causes of B1255
- Faulty MICU
- Faulty combination switch control unit
- Combination switch control unit harness is open or shorted
- Combination switch control unit circuit poor electrical connection
- Corroded or loose connector pins on the data link
How to fix B1255
- Confirm the code with a scan tool and check every module on the system for related faults
- Inspect the connectors at both ends of the data link for corrosion, moisture, and loose pins
- Test the data link wiring for opens and shorts with a multimeter
- Repair any damaged wiring or connector before replacing a module
- Replace the combination switch control unit that fails testing, then clear codes and retest
Sources and review
- Last updated 2026-09-29.