K-Line Frame Analysis & Automotive Data Analyzer Tool

Introduction : The legacy K‑Line bus (including ISO 9141 and KWP2000) is a single wire serial protocol used in older vehicle diagnostic and control systems.

KWP2000 Over K-Line Frame Structure

It consists of defined frame structure which includes Format, Target address, source address, length, service ID, data and check sum.

KWP2000 supports two header formats:

  1. Short Header (3-byte header) : used when data length <= 63 bytes

  2. Long Header (4-byte header) : used when data length > 63 bytes

K-line KWP2000 Frame

FieldSizeDescription
Format Byte1 BytePCI – Protocol Control Information; Tells the ECU/tester the length of the upcoming data section. Defines that the message is short header (Bit7=0).
Target Address1 ByteIdentifies which ECU the frame is for.
Source Address1 ByteIdentifies the sender of the frame.
Length Information2 bytesLEN_L and LEN_H together encode data length using Length = (LEN_H × 256) + LEN_L; Supports messages up to 4095 bytes.
Service ID1 ByteFirst byte of Data field. Specifies the diagnostic service or command being executed. Example : 0x10 – Start Diagnostic Session
Data Bytes0-63 bytesProvides arguments required by the Service ID.
Checksum1 byteVerify integrity of the entire frame.

K-line Bus Data logger tool

ManufacturersProduct/features
Vector InformatikVN1600 series interface supports K-Line along with CAN, LIN etc.
Diagcode Ltd.OBDII Logger : It has K-line channels to capture and log K-line traffic. Another tool is J2534 Logger.
Influx TechnologyRebel LT : Analyses K-line and CAN protocols.
Accurate Technologies Inc. (ATI)DLX Datalogger : one ISO 9141 compliant K-Line channel and two high speed CAN 2.0B channels
AutoPi.ioAutoPi Mini is a plug-and-play device which comes with integrated K-line and CAN interface.

Summary: A K-Line frame analysis and data analyzer tool gives visibility into these legacy networks, enabling service engineers to decode, log and troubleshoot historic vehicle communication systems that are still in operation.