Fault code U1750 – a step-by-step guide to diagnosing and fixing it

Error code U1750 is displayed and the check engine light is on - what does this mean?

The DTC U1750 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 CAN bus network and the communication between the engine control unit and other electronic modules in the vehicle.

What can cause this error code?

• Defective CAN bus wiring or short circuit
• Damaged plug connections on the control units
• Faulty terminating resistors in the CAN bus system
• Defective engine control unit or other ECU modules
• Corrosion or moisture in the electrical connections
• Broken earth cable or poor earth connection
• Voltage fluctuations in the on-board power supply
• Software error in the control units

What symptoms occur in parallel with fault code U1750?

• Communication faults: Various vehicle systems are not functioning properly
• Loss of engine power: Reduced power or irregular engine running
• Starting problems: The vehicle is difficult or impossible to start
• Warning lights: Multiple warning lights illuminate simultaneously
• Failure of comfort functions: Air conditioning, radio or other electronic systems do not work
• Shifting problems: Shifting errors can occur with automatic transmissions
• Unstable idling: engine runs unevenly at idle speed

How can the problem with fault code U1750 be resolved?

• Correcting fault code U1750 requires a systematic diagnosis of the communication systems. The following solutions can solve the problem:
• Checking and repairing the CAN bus wiring with a multimeter, replacing damaged cables and ensuring that the data lines are twisted correctly
• Clean and replace all plug connections between the control units, use contact spray and check for tight fit
• Measuring and replacing the terminating resistors in the CAN bus system, typically 120 Ohm should be measured between CAN High and CAN Low
• Software update or reprogramming of the affected control units at the authorized dealer or in a specialist workshop
• Check and repair the ground connections, clean corrosion and ensure good electrical contacts
• Checking the vehicle electrical system voltage and repairing problems in the charging system or battery
• Replacement of defective control units after clear identification through professional diagnosis