Fault code B1868 – a step-by-step guide to diagnosing and fixing it

Error code B1868 is displayed and the check engine light is on - what does this mean?

The DTC B1868 is a manufacturer-specific fault code that is recognized by the OBD/EOBD system and typically indicates problems with the body electronics or comfort systems. This trouble code usually refers to malfunctions in the electrical wiring, sensors or control units of the vehicle body. The exact definition of this fault code may vary depending on the vehicle manufacturer.

What causes can this fault code have?

• Defective body control module (BCM)
• Damaged wiring to comfort systems
• Loose or corroded plug connections
• Defective door handle sensor or locking cylinder sensor
• Faulty central locking system
• Defective interior lighting or its control unit
• Problems with the anti-theft alarm system
• Voltage fluctuations in the on-board power supply
• Defective fuses or relays

What symptoms occur in parallel with fault code B1868?

• Malfunctions in the central locking system: The doors cannot be locked or unlocked properly
• Problems with the interior lighting: Lighting does not work or does not switch on/off automatically
• Malfunctions of the comfort functions: Electric windows, seat adjustment or mirror adjustment work incorrectly
• Malfunctions of the alarm system: anti-theft alarm system triggers for no reason or does not work
• Vehicle access problems: Keyless entry system does not respond or works unreliably

How can the problem with error code B1868 be rectified?

• Repairing EOBD error code B1868 requires a systematic diagnosis of the affected systems.
• Perform a complete system diagnosis: Using a professional OBD scanner, read all control units, clear fault memory and test drive to identify the exact cause
• Check wiring and plug connections: Check all electrical connections to the body systems for damage, corrosion or loose contacts and repair or replace if necessary
• Replace body control module: If the BCM is faulty, replace control unit and then have it programmed to restore all comfort functions
• Check fuses and relays: Check all relevant fuses and relays in the body electronics and replace defective components
• Test sensors and actuators individually: Check door handle sensors, locking cylinder sensors and other affected components individually and replace if defective
• Check the power supply: Measure the vehicle electrical system voltage and carry out appropriate repairs if there are problems with the alternator or battery