Fault code U1017 – a step-by-step guide to diagnosing and fixing it

Error code U1017 is displayed and the check engine light is on - what does this mean?

The DTC U1017 is a manufacturer-specific communication error code that is recognized by the OBD and EOBD systems when problems occur in data transmission between different control units. This trouble code mainly affects the network communication system and can have different meanings for different vehicle manufacturers, often indicating problems with the CAN bus or other communication networks.

What causes can this error code have?

• Defective CAN bus lines or cable breaks
• Faulty control unit communication
• Loose or corroded plug connections
• Defective gateway module
• Interrupted ground connections
• Short circuits in the communication network
• Faulty terminating resistors in the CAN system
• Defective body control module (BCM)
• Interference due to electromagnetic interference
• Software errors in the control units

What symptoms occur in parallel with fault code U1017?

• Communication problems: Various vehicle systems are not functioning properly
• Starting problems: The vehicle may not start
• Failure of electrical components: Lighting, air conditioning or other systems are malfunctioning
• Warning lights: Multiple indicator lights may come on at the same time
• Instrument panel problems: Gauges work intermittently or not at all
• Engine power loss: Reduced power due to communication errors between control units
• Shifting problems: Automatic transmission shifts erratically or stays in one gear

How to fix the problem of fault code U1017?

• Repairing fault code U1017 requires a systematic diagnosis of the communication systems.
• Check and repair the CAN bus cables: Inspect all communication cables for damage, cable breaks or short circuits and replace defective cables
• Clean and secure plug connections: Disconnect all relevant connectors, clean with contact spray, check for corrosion and reconnect firmly
• Update control unit software: Have the latest firmware for all affected control units installed at authorized workshops
• Replace gateway module: Replace the central communication module if it has been identified as the source of the fault
• Check and replace earth connections: Clean all ground points in the affected area and ensure that they are properly connected
• Measure and replace CAN bus terminating resistors: Check the 120 ohm terminating resistors at both ends of the CAN bus and replace if necessary
• Eliminate sources of electromagnetic interference: Identify and repair retrofitted electronic components or defective ignition cables