KWP vs UDS: Keyword Protocol & Unified Diagnostic Services are and diagnostics specifications from the vehicle manufacturers. KWP – Basic Information. KWP is a Uart based data link protocol uses ISO K and L line for signal communication. K – Line” is. Protocols – KWP (ISO and ISO ), UDS (ISO ) range of OBD specifications for cars and commercial vehicles to create one regulation.

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KWP functionalities for measurement value transfer and error memory management were improved for UDS standards. This helps in closely monitoring vehicle condition in regular intervals. In addition, there is an optional L-line for wakeup. KWP uses following services for error memory management: Retrieved 10 May Commonly used physical layers [ edit ] One underlying physical layer used for KWP is identical to ISOwith bidirectional serial communication on a single line called the K-line.

The exchange of messages between testing device and the vehicle ECU forms the basis of the diagnostic system. But it also calls for additional requirement for ECU memory along with extra development costs.


The data rate is between 1. By proceeding without prltocol your settings, you agree with us. The KWP protocol uses a physical layer, identical to ISOfor bidirectional serial communication over K-line with the controller. With the help of the additional sub functions, UDS enables the tester to collect more diagnostic information.

KWP CAN – CAN-based protocols for diagnostic services

This protocol covers the application layer in the OSI model of computer networking. Both the diagnostic protocol facilitate exchange of protocok and command messages from the test equipment to the automotive ECU; and key measurement values data in response from the vehicle ECU.


KWP on the K-Line was the first standardized diagnostic protocol used in Europe on a large scale. Let us have a look at two protocols in detail:.

Protocols for programming interfaces – KWP, UDS, SAE

Thus, UDS as a diagnostic protocol paves way for added services and functionalities. Imprint Privacy Policy Company Details. Newsletter You want to keep informed.

We are member of the following associations: Specificatiin cookies can be disabled at any point. The vehicle ECU may respond to the periodic request with one or several data record values. Select Division Select Division. But, there is a key difference between the two protocols in the way these measurement values are exchanged between the tester and ECU: Automotive technologies Technology stubs.

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This makes considerably higher data rates available. Otherwise, these days UDS protocol is the go to standard for vehicle diagnostics.

As implementation and standardization ran concurrently, we have considerable experience that led to the implementation of the protocol for our diagnostic services. While, UDS protocol can be seen as a superset of the KWPsince it is derived from the latter, a comparison of both as the diagnostic protocols gives out some interesting facts: What sub functions and parameters are important to be considered for UDS implementations?

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Support for in-vehicle communication networks: More details can be found in your privacy policy. This means increased efficiency of data exchange. The average data rate of KWP is between 1. We use cookies to ensure the best experience on our website. UDS protocol is defined by redundancy of functionalities whereby various UDS services can be used to execute a certain specificaiton function.


You can help Wikipedia by expanding it. KWP also covers the session layer in the OSI model, in terms of starting, maintaining and terminating a communications session.

To cater to this need of the hour, various vehicle diagnostic protocols were conceptualized and developed. Moreover, in a periodic communication sequence based on UDS standard, the test equipment sends periodic requests for updated information from automotive ECUs.

KWP favors symmetrical communication sequence where the number of request and response messages between the testing device and server are symmetrical. What services are necessary for you? One underlying physical layer used for KWP is identical to ISOwith bidirectional serial communication on a single line called the K-line. KWP can be implemented on CAN using just the service layer and session layer no header specifying length, source and target addresses is used and no checksum is used ; or using all layers header and checksum are encapsulated within a CAN frame.

Thus it is important to ponder over certain questions, before deciding on the implementation of UDS services for your application, listed as:. Hence number of requests and response between the tester and the ECU can vary.

Imprint Privacy Policy Company Details. ISO and SAE Society of Automotive Engineers introduced various diagnostic protocols and standards, designed to cater to the different types of automotive ECU systems and diagnostics specifications from the vehicle manufacturers. For the first time, it enabled the diagnostics and flash programming of a large number of ECUs via central diagnostic access. Transfer of Key Measurement Values: