ELM 327 OBDDavide Mazza

Sapienza University of Rome – DIAG – Pervasive Systems

https://github.com/davidemazza

https://www.linkedin.com/in/davide-mazza-33a9b291

Produced by ELM Eletronic (v. 1.0 – 2005)

Programmed microcontroller 

Translate the on-board diagnostic (OBD) interface 

Bluetooth

Interface both PC and Smartphone

Compatible with all cars that respect the generic OBD standard

Last Version 2.1

What is it ELM 327?

What is it OBD?

On-board diagnostics (OBD)

Vehicle's self-diagnostic and reporting capability

Introduce in the 1980s – Only idiot light

Modern OBD – Real-time data

Different Standard Interfaces

ELM 327 use OBD-II

OBD II

PINOUT

ELECTRICAL SIGNALLING PROTOCOLS AVAILABLE

SPECIFIES

TYPE OF DIAGNOSTIC CONNECTOR

MESSAGING FORMAT

OBD II

Protocols ELM 327

SAE J1850 PWM – pin 2 and 10

SAE J1850 VPW - pin 2

ISO 9141-2 - pin 7 and 15 (optional)

ISO 14230-4 KWP - pin 7 and 15 (optional)

ISO 15765-4 CAN – pin 6 and 14

SAE J1939

1 89 16

Protocols ELM 327  ELM 320 ELM 322 ELM 323 ELM 325 ELM 327 ELM 328 ELM 329

  SAE J1850-PWM X       X    

  SAE J1850-VPW   X     X    

  ISO 9141-2     X   X    

  ISO 14230-4 (slow)     X   X    

  ISO 14230-4 (fast)     X   X    

  ISO 15765-4 (CAN)         X   X

  SAE J2411 (SWCAN)         X   X

  KW1281 (SAE J2818)              

  SAE J1939 (250kbps)          X   X

  SAE J1939 (500kbps)         X   X

  SAE J1708 (J1587)       X      

  SAE J1708 (J1922)       X      

Engine RPM Calculated Load ValueCoolant Temperature Vehicle Speed Short and Long Term Fuel Trim Intake Manifold Pressure Timing Advance Intake Air Temperature Air Flow Rate Absolute Throttle Position Oxygen sensor voltages Fuel System status and Pressure Other . . .

Sensor Data

How to use: test phase

Egine ECU diagnostics tool that uses a cheap Bluetooth ELM / OBD adapter to connect to your car OBD2 engine management system

Android App (available on Google PlayStore)

Record Data Trips Widget Sensor Different display types DTC trouble codes Connection also GPS Upload data logs

Torque Lite (OBD2 & Car)

My personal Trip with Torque Lite

How to use: test phase

My personal Trip with Torque Lite

How to use: test phase

My ApplicationOBD App

OBD is a basic application for the connection with your ELM 327.

Detection data in real time. Update data NOT delete

( comparison)

Android App (available here and with qrcode)

Choose which data sensor see Real time update data sensor List of your trips Select obd protocol Compass

GitHub repository: https://github.com/davidemazza/OBDApp

API

API

Code

Code

Code

OBD App

OBD App

Live Demo

Thanks!