ISO 11898-3 Low-speed CAN (Single Wire CAN): Reliable Communication for Non-Critical Systems

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ISO 11898-3, also known as Low-speed CAN or Single Wire CAN, is a standardized communication protocol based on Controller Area Network (CAN) technology, designed for vehicle systems where high data transfer speeds are not required. This protocol is commonly used for non-critical systems such as windows, lighting, comfort sensors, and climate control.

How Low-speed CAN Works

Low-speed CAN uses a single-wire communication line between ECU modules. The standard supports data transfer rates up to 125 kb/s, providing reliable and resilient communication even in environments with electromagnetic interference.

Key features include:

  • Simple physical layer, reducing implementation costs
  • Error detection and message retransmission
  • Efficient data transfer for non-critical vehicle systems

Launch OBD-II adapters that support the protocol:

DBScar I, DBScar II, DBScar III, DBScar IV, DBScar V, DBScar VII

ThinkDiag devices that support the protocol:

ThinkDiag, ThinkDiag 2

Ediag devices that support the protocol:

Ediag YA-101, Ediag YA-201, Ediag Plus, Ediag Elite

Vehicle types and brands supported by the protocol:

Passenger and light commercial vehicles from European and American manufacturers, including Volkswagen, Audi, BMW, Mercedes-Benz, Ford, GM, as well as vehicles with comfort and auxiliary systems (e.g., ABS, ESP, climate control); typically models from 2003 onward.

Low-speed CAN uses a single wire and lower speed for less critical vehicle systems.

Advantages of ISO 11898-3 Low-speed CAN

  • Lower implementation costs compared to high-speed CAN
  • Reliable communication for non-critical systems
  • Standardized and compatible with different vehicle types
  • Enables simple diagnostics and monitoring of module functionality
  • Ideal for comfort and auxiliary systems in vehicles

Disadvantages and Limitations

  • Low data transfer speed (up to 125 kb/s) limits throughput
  • Not suitable for critical systems such as ABS or engine control
  • Requires compatible diagnostic tools
  • Limited to vehicles equipped with Single Wire CAN networks

Applications of Low-speed CAN

Low-speed CAN is used to control and diagnose non-critical systems, including electric windows, central locking, lighting, and climate control. Its simplicity and reliability make it ideal for comfort and auxiliary modules in vehicles.

Conclusion

ISO 11898-3 (Low-speed / Single Wire CAN) provides a reliable and cost-effective standard for the communication and diagnostics of non-critical vehicle systems. Its ability to reduce implementation costs while maintaining reliability makes it essential for managing auxiliary functions in modern automobiles.