Fault code U2013 – a step-by-step guide to diagnosing and fixing it

Error code U2013 is displayed and the check engine light is on - what does this mean?

The DTC U2013 is a network trouble code that is recognized by the OBD and EOBD systems when communication problems occur between different ECUs in the vehicle. This trouble code specifically indicates that the data transmission between the engine control unit and other electronic modules is faulty. Different manufacturers may have slightly different names for this fault code, but it always refers to network communication errors.

What causes can this fault code have?

• Defective CAN bus cabling
• Damaged plug connections between control units
• Corroded or loose earth connections
• Faulty terminating resistors in the CAN bus system
• Defective engine control unit or other ECU modules
• Malfunctions due to electromagnetic interference
• Interrupted or short-circuited data lines
• Voltage problems in the on-board power supply

What symptoms occur in parallel with fault code U2013?

• Starting problems: The vehicle is difficult or impossible to start
• Loss of power: Reduced engine power and poor acceleration
• Irregular idling: Engine runs unevenly or stutters at idle speed
• Failure of comfort functions: Air conditioning, radio or other electrical systems do not work
• Multiple warning lights: Various indicator lights in the dashboard illuminate simultaneously
• Shifting problems: Shifting errors can occur with automatic transmissions
• ABS or ESP malfunctions: Driving assistance systems can fail

How to fix the problem of error code U2013?

• Repairing this network fault code requires a systematic diagnosis of the electronic communication systems.
• Perform full OBD diagnostics and read out all stored error codes, then test the CAN bus system with professional diagnostic equipment and locate and replace defective lines
• Check and clean all plug connections between the control units and replace the entire connectors if they are corroded or damaged
• Measure the vehicle electrical system voltage and earth connections, stabilize fluctuating voltages and clean and tighten all earth points
• Check CAN bus terminating resistors with a multimeter and replace defective resistors with new ones with correct values
• Test individual control units in isolation, identify defective ECU modules and replace with new or overhauled units
• Visually and electrically check the complete wiring of the data bus, repair or completely replace damaged wiring harnesses