[UDS unified diagnosis service] IV. typical diagnosis service (1) - diagnosis and communication management function unit

Four 、 Diagnose typical services （1）— Diagnosis and communication management function unit

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link ：https://download.csdn.net/download/sinat_40003796/85031818

Diagnostic service of each functional unit ：

• Diagnosis and communication management function unit
• Data transmission function unit
• Read fault information function unit （ Storage data transmission function unit ）
• Online programming function unit （ Upload and download function unit ）
• function / Component test function unit （ Routine function unit ）
• Input / output control unit （0x2F）

This article mainly explains “ Diagnosis and communication management function unit ”, For the rest, see other articles .

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Before the official start , You can understand the content below , It is very helpful for follow-up study ！

Standard documents ：

Service identifier SI：

Nouns and abbreviations ：

Summary of common diagnostic services ：

Negative response code ：

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“ Diagnosis and communication management function unit ” Services included ：

（1）DiagnosticSessionControl (0x10) service

Function ：

• Used to enable different diagnostic sessions in the server

  The following figure for “ State transition diagram of diagnostic session mode ”：
  

Request message ：

Subfunction parameters （Subfunction）：

Definition of subfunction parameters ：

• 1 Bytes of data
• Bit7： Disable positive response indicator bit suppressPosRspMsgIndicationBit
  0=False： Need a positive response
  1=True： Positive responses are prohibited
• Bit6-0： Subfunction parameter values （0x00~0x7F）

Diagnostic services allowed for different sessions ：

Positive response ：

Supported negative response code ：

• 0x12: The subfunction of requesting service is not supported
• 0x13: The data length of the request message ( Or format ) Not up to standard
• 0x22: Condition not satisfied

Example ：

（2）TesterPresent (0x3E) service

Function ：

• Used to indicate to the server that the diagnostic instrument is still connected to the network , Previously activated specific diagnostic services and / Or the communication function remains active
• Send periodically
• 0x3E The purpose of is to keep the server in the non default mode in its original state , Do not enter the default mode .

Request message ：

Positive response ：