Fault code B1806 – a step-by-step guide to diagnosing and fixing it

Error code B1806 is displayed and the check engine light is on - what does this mean?

The DTC B1806 is a body control module fault code that is recognized by the OBD/EOBD system and indicates a problem with the vehicle's body electronics. This trouble code typically refers to faults in the electrical wiring or the control modules of the body electronics. Depending on the vehicle manufacturer, the specific meanings and affected systems may vary.

What causes can this error code have?

• Defective body control module (BCM)
• Damaged wiring in the body area
• Corroded or loose plug connections
• Defective fuses or relays
• Problems with the vehicle battery or alternator
• Faults in the CAN bus communication
• Water damage to electronic components
• Defective sensors in the body area

What symptoms occur in parallel with fault code B1806?

• Lighting problems: Headlights, tail lights or interior lighting do not work properly
• Electrical failures: Power windows, central locking or other electrical systems operate unreliably
• Warning lights: Various indicator lights in the dashboard illuminate continuously
• Starting problems: The vehicle is difficult or impossible to start
• Communication errors: Malfunctions between different control units
• Intermittent failures: Electrical systems work sporadically

How to fix the problem of error code B1806?

• The repair requires a systematic diagnosis of the body electronics.
• Complete inspection and replacement of the body control module according to manufacturer specifications
• Thorough inspection and repair of all cable connections in the body area with subsequent function test
• Cleaning or replacement of corroded plug connections and ensuring watertight connections
• Replacement of defective fuses and relays according to the vehicle's wiring diagram
• Battery test and, if necessary, replacement and alternator performance check
• CAN bus diagnostics with professional diagnostic device and repair of communication lines
• Drying and sealing of water-damaged components or complete replacement