Code Definition

B1005 — Multiplex integrated control unit communication with relay control module lost

System: Body  |  Type: Manufacturer-Specific  |  Make: Honda

About B1005

B1005 is a manufacturer-specific body diagnostic trouble code recorded for Honda vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

B1005 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Honda Multiplex Integrated Control Unit (MICU) is a central body electronics module that coordinates communication between various electrical subsystems including lighting, power windows, door locks, and accessory circuits. DTC B1005 is set when the MICU detects a loss of communication with the Relay Control Module, which is responsible for managing power distribution to key electrical loads throughout the vehicle. The MICU monitors the serial communication link to the Relay Control Module and sets this code when valid data is no longer received within a defined timeout period. When this f...

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