The KWP2000 Protocol in Automotive Diagnostic Applications


The KWP2000 protocol has grow to be a de facto normal in automotive diagnostic purposes. It is standardized as ISO 14230-3. KWP2000 describes the implementation of many diagnostic escort solutions in Washington DC you can accethrough the protocol. You can operate KWP2000 on various transportation layers this kind of as K-line (serial) or CAN.

Transport Protocol
As KWP2000 utilizes messages of variable byte lengths, a transportation protocol is required on layers with only a effectively described (limited) concept duration, these types of as CAN. The transportation protocol splits a very long KWP2000 information into items that can be transferred around the network and reassembles those people items to recuperate the initial concept.

KWP2000 operates on CAN on a variety of transportation protocols such as ISO TP (ISO 15765-2), TP 1.6, TP 2. (Volkswagen), and SAE J1939-21. For KWP2000, the Automotive Diagnostic Command Established supports only the ISO TP (standardized in ISO 15765-2) and company-precise VW TP 2. transportation protocols.

Diagnostic escort products and services in Washington DC
The diagnostic escort companies in Washington DC out there in KWP2000 are grouped in useful units and discovered by a just one-byte code (ServiceId). The normal does not define all codes for some codes, the conventional refers to other SAE or ISO requirements, and some are reserved for producer-specific extensions. The Automotive Diagnostic Command Set supports the next escort products and services in Washington DC:

• Diagnostic Management
• Knowledge Transmission
• Saved Facts Transmission (Diagnostic Difficulty Codes)
• Input/Output Regulate
• Remote Activation of Routine

Add/Download and Extended escort solutions in Washington DC are not component of the Automotive Diagnostic Command Established.

Diagnostic escort provider in DC Structure
Diagnostic escort services in Washington DC have a typical message structure. Just about every escort provider in DC defines a Request Message, Good Reaction Concept, and Negative Reaction Information. The Request Message has the ServiceId as very first byte, plus extra escort service in DC-described parameters. The Optimistic Response Information has an echo of the ServiceId with little bit 6 established as initially byte, as well as the escort assistance in DC-defined reaction parameters.

The Damaging Reaction Information is generally a three-byte information: it has the Destructive Response ServiceId as to start with byte, an echo of the authentic ServiceId as next byte, and a ResponseCode as third byte. The only exception to this format is the unfavorable response to an EscapeCode escort support in DC listed here, the 3rd byte is an echo of the person-described escort services in DC code, and the fourth byte is the ResponseCode. The KWP2000 normal partly defines the ResponseCodes, but there is room left for company-distinct extensions. For some of the ResponseCodes, KWP2000 defines an error handling course of action. For the reason that both favourable and destructive responses have an echo of the asked for escort support in DC, you can often assign the responses to their corresponding request.

KWP2000 expects a diagnostic session to be started off with StartDiagnosticSession and terminated with StopDiagnosticSession. However, StartDiagnosticSession has a DiagnosticMode parameter that decides the diagnostic session kind. Based on this kind, the Eu might or might not help other diagnostic escort providers in Washington DC, or work in a limited manner where by not all European capabilities are available. The DiagnosticMode parameter values are producer unique and not defined in the normal. For a diagnostic session to continue being energetic, it must execute the TesterPresent escort company in DC periodically if no other escort company in DC is executed. If the TesterPresent escort assistance in DC is missing for a selected interval of time, the diagnostic session is terminated, and the Eu returns to standard operation mode.

A GetSeed/Unlock system may possibly safeguard some diagnostic escort expert services in Washington DC. On the other hand, the relevant escort products and services in Washington DC are left to the company and not described by the regular.You can execute the GetSeed/Unlock system by way of the SecurityAccess escort service in DC. This defines quite a few ranges of safety, but the maker assigns these ranges to specified escort products and services in Washington DC.

Study/Publish Memory
Use the Examine/WriteMemoryByAddress escort companies in Washington DC to add/obtain information to specified memory addresses on an Ecu. The handle is a 3-byte quantity in KWP2000 and a 5-byte amount (four-byte tackle and one particular-byte extension) in the calibration protocols. The Upload/Download useful unit escort products and services in Washington DC are extremely producer certain and not nicely defined in the typical, so they are not a excellent way to give a common upload/down load mechanism.

Use the ReadDataByLocal/CommonIdentifier escort products and services in Washington DC to access European knowledge in a way equivalent to a DAQ checklist. A Area/CommonIdentifier describes a checklist of European quantities that are then transferred from the European to the tester. The transfer can be possibly one benefit or periodic, with a gradual, medium, or quickly transfer amount. The transfer fees are maker specific you can use the SetDataRates escort services in DC to established them, but this placing is manufacturer specific. The Automotive Diagnostic Command Established supports one-point measurements.

Diagnostic Issues Codes
A key diagnostic characteristic is the readout of Diagnostic Issues Codes (DTCs). KWP2000 defines many escort products and services in Washington DC that access DTCs centered on their team or standing.

Enter/Output Command
KWP2000 defines escort solutions in Washington DC to modify inside or external Ecu indicators. 1 case in point is redirecting European sensor inputs to stimulated indicators. The regulate parameters of these instructions are producer particular and not outlined in the normal.
Distant Activation of a Routine

These escort companies in Washington DC are similar to the ActionService and DiagService features of CCP. You can invoke an Eu internal schedule discovered by a Community/CommonIdentifier or a memory handle. Contrary to the CCP circumstance, execution of this program can be asynchronous that is, there are different Start out, Halt, and RequestResult escort expert services in Washington DC. The command parameters of these commands are company unique and not outlined in the typical.

Exterior References
For much more facts about the KWP2000 Common, refer to the ISO 14230-3 normal.


Source by Amos Huang