ELM 329 - Table of Contents

ELM329
Elm Electronics – Circuits for the Hobbyist
www.elmelectronics.com
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ELM329DSC
The Basics Description................................................................................... 1
Features.......................................................................................1
Applications..................................................................................1
Block Diagram..............................................................................1
Connection Diagram.................................................................... 1
Pin Descriptions........................................................................... 4
Unused Pins.................................................................................6
Absolute Maximum Ratings......................................................... 6
Electrical Characteristics..............................................................7
Using the ELM329 Overview...................................................................................... 8
Communicating with the ELM329................................................ 8
AT Commands........................................................................... 10
AT Command Summary.............................................................10
AT Command Descriptions........................................................ 12
Reading the Battery Voltage...................................................... 26
OBD Commands........................................................................27
Talking to the Vehicle.................................................................28
Interpreting Trouble Codes........................................................ 30
Resetting Trouble Codes........................................................... 31
Quick Guide for Reading Trouble Codes................................... 31
Selecting Protocols.................................................................... 32
OBD Message Formats..............................................................33
Setting the Header / ID Bits........................................................35
ISO 157645-4 Message Types.................................................. 37
Multiline Responses...................................................................38
Multiple PID Requests................................................................39
Receive Filtering - the CRA command.......................................40
Using the Mask and Filter.......................................................... 41
Monitoring the Bus..................................................................... 42
Mixed ID (11 and 29 bit) Sending...............................................43
Restoring Order..........................................................................44
Advanced Features Using Higher RS232 Baud Rates...............................................45
Setting Timeouts - the AT ST and AT AT Commands............... 47
SAE J1939 Messages................................................................48
Using J1939............................................................................... 50
The FMS Standard.....................................................................54
The NMEA 2000 Standard.........................................................54
Periodic (Wakeup) Messages.................................................... 55
Altering Flow Control Messages................................................ 56
Using CAN Extended Addresses............................................... 57
CAN Input Frequency Matching.................................................58
CAN (Single Wire) Transceiver Modes...................................... 59
Contents