Fault code U2000 – a step-by-step guide to diagnosing and fixing it

Error code U2000 is displayed and the check engine light is on - what does this mean?

The DTC U2000 is recognized by the OBD system when a communication error occurs in the vehicle's CAN bus network (Controller Area Network). This trouble code indicates an interruption or fault in the data transmission between different control units. For various manufacturers, this fault code may also be referred to as a "CAN bus communication error" or "network communication error".

What causes can this error code have?

• Defective CAN bus wiring
• Damaged or corroded plug connections
• Failed control unit (ECU)
• Defective CAN bus terminating resistor
• Short circuit in the CAN bus cable
• Voltage problems in the vehicle electrics
• Faulty gateway modules
• Water damage to electronic components

What symptoms occur in parallel with fault code U2000?

• Starting problems: The vehicle is difficult or impossible to start
• Failure of comfort functions: Electric windows, air conditioning or radio do not work
• Irregular engine running: Engine runs unevenly or stalls when idling
• Warning indicators: Multiple indicator lights illuminate simultaneously
• ABS/ESP malfunctions: Anti-lock braking system and stability control are impaired
• Communication error: Diagnostic device cannot reach all control units

How can the problem with error code U2000 be rectified?

• Repairing error code U2000 requires a systematic approach to localizing the communication fault.
• Check and repair the CAN bus wiring: Check all CAN bus cables for damage, breaks or short circuits and replace defective cables
• Clean and secure plug connections: Disconnect all relevant plugs, clean with contact spray and reconnect firmly
• Measure terminating resistors: Check CAN bus terminating resistors with a multimeter (should be 60 ohms between CAN high and CAN low) and replace if necessary
• Test control units individually: Check the functionality of each connected control unit in isolation and replace defective modules
• Check the power supply: Check and correct the vehicle electrical system voltage and ground connections of all CAN bus participants
• Replace gateway module: If faults are detected in the central gateway module, replace it with a new one