OBD2 Model B, unable to connect

[Zouritte]

Hi everyone,
First of all, i wish all of you a happy new year 2016

I have a OBD-II I2C Adapter "Built in Motion Sensor" for Arduino, that i can't get connected to my car.

I have a Land Rover that runs on CAN 11bit 500kb protocol.
My adapter is connected to the arduino UNO as follow:
- red -> 5V
- black -> GND
- white -> A4 (SDA)
- green -> A5 (SCL)

I have tried to run both rpm_led-i2c program and obd_i2c_test without success.(tried UART as well....just to be sure)
the obd_i2c_test program displays "Timeout" after each ATZ, ATL1, ATH0, ATRV, 0100, 010C, 0902 request.


Do you have an idea on how to fix it ?

I know my OBD2 port works on my car as i have a commercial reader that i use daily for basics engine data.

Thank you for your help.

Tim

[stanley]

If even ATZ has a timeout response, it indicates the I2C communication is not through. Is the LED inside the enclosure blinking?

[Mare-Božo]

Hi staneley.

I have a similar problem.
My system is not Arduino but STM32 board (3.3Vcc).
5V -> not connected ( have a 3.3V on STM32 board)
GND -> connected with GND board
White -> SDA (board working on GND to 3.3V level)
Green-> SCL (board working on GND to 3.3V level)

I2C speed is 1k to 100k. I try many different setups..
I also try with USART (38400 boud), but without progress....

When is OBD powered it start to blink, then stop.
I also measure current on 16pin. On plug in (start-power on) is 25mA then fall on 2mA.

With USART it don't receive any character... device do not blik with any LED.... (AT\r, ATZ\r, ATRV\r...)
With I2C i get error -> "NO DEVICE". I check with oscilloscope... no ACK after sending address on slave.
7-bit SLAVE ADDR = 0x62.
I alos try to address other two sensors with address 0x68 and 0x69, but without success...
What am I doing wrong?
Has OBD adapter internal pull up resistors for I2C?
Is any tech documentation for freematics OBD-II adapter?
What speed of communication should be used for I2C?

[Mare-Božo]

Should OBD-II adapter respond on I2C slave address (0x62) with ACK if is just connected on 12V (4-5 pin GND, 16 to 12V), without car comunication?

[Mare-Božo]

Problem solved!

Data and clock wire is incorrectly soldered.
white is SCL/CLK
green is SDA/DATA

[stanley]

Sorry for that. The line color has changed in the latest batch. I've corrected the information on our web pages.