Automotive most used protocols – KWP2000 and UDS.


KWP2000/UDS devices are essential tools for anyone who wants to tinker with a vehicle’s onboard computer system. Whether you’ll use yours for chip tuning a hobby-racing vehicle or you need to equip your auto-shop business with better on-board vehicle diagnostics (OBD) programming tools.

KWP2000 actually stands for Keyword Protocol 2000, which is the name of a set of communications codes employed by vehicle computers and systems that meet the OBDII regulatory standard. Diagnostic scanners and programmers that use KWP2000 code transfer data to your vehicle’s electronic control unit, or ECU. Unified Diagnostic Services (UDS) is a diagnostic communication protocol as well, which is specified in the ISO 14229-1. It is derived from ISO 14230-3 (KWP2000) and ISO 15765-3 (Diagnostic Communication over Controller Area Network (DoCAN)).

What are the difference between KWP2000 & UDS?

  1. Event triggering and periodic transmission are applicable only in UDS.
  2. Positive response supression  for tester present is not present in KWP2000.
  3. Transfer of measurement values,  only two-byte identifers are available in UDS. In KWP2000 one byte record Local Identifer and Two Byte  Common Identifer
  4. Error memory management.

Differences between KWP 2000 and UDS

The classic diagnostic communication with KWP protocols has favored a symmetrical number of requests and responses. In contrast, UDS provides event-driven and periodic services, for which the number of requests and responses can differ greatly. The KWP 2000 principles to transfer measurement values and to manage the ECU´s error memory were re-engineered for the UDS standard.


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