Connecting a Vehicle ECU Simulator to an IoT backend platform with the FATBOX G3 Gateway


Cloud monitoring vehicle data via CAN Bus ISO15765-4 & J1939 and 4G/LTE/3G

  • In this tutorial, we will set up a OZEN Elektronik OE91C1610 CAN BUS ECU simulator that is compatible with IS015765-4 (part of OBD2) to interface with the FATBOX G3 gateway’s CAN bus interface and connect to AWS IoT. To also see our tutorial for CAN Bus J1939 (heavy vehicles) Click here.

  • Our G3 gateway is based on the iMX6 CPU with built-in CAN port functionality. The CAN bus is driven by an industrial proven high speed CAN transceiver that provides a robust & reliable interface with high noise immunity.

  • We will also look at connecting the G3 IOT Gateway to a designated Cloud Service. Supported clients are AWS IoT, Azure IoT Hub and Ubidots.

  • Users have the option of backhaul via either cellular (4G/3G), WIFI or wired Ethernet, depending on version


Hardware Wiring







OZEN Elektronik OE91C1610 (J1962 female OBD)

G3 CAN BUS port (DB9 male)




CAN High



Above shows the CAN BUS signal connection usually implemented using shielded twisted pair cable.

You can use a standard off-the-shelf ‘OBD2 male to DB9 female cable’ with pin connection as below:

ODB2-DB9 Cable.png
DB9 to OBD2.png

Ozen ECU simulator Configuration

Use the DIP switch on the board to select CAN frame ID 11-bit type. 

For the CAN BUS baud rate, select 250 kbps. 

DIP Switch CAN config.png

The baud rate set on the G3 gateway CAN BUS must be same.


Connect the ECU Simulator to Gateway

Our gateway uses a configuration file (\user\iotasset.txt) to map the required Parameter IDs (PIDs) to be read during each polling cycle. This flexibility allows wide compatibility with different CAN Bus devices from different manufacturers.

To write this iotasset.txt file we will be referencing the PIDs table from the product user manual (see sample below):

ECM Table.png

And here is a sample of the iotasset.txt.


In the top example, we are configuring to read ECT (Engine Coolant Temperature) PID.

  • “7DF” is the functional address of ECU which based on ISO-15765-4 11-bit protocol.

  • “7E8” is the response message ID used to filter the response message from the query.

  • “0105” is the CAN request ECM mode 01 & PID 05.

  • Response data is located at offset +3 from first byte and length of 1 byte. 

  • Name data field name, as “EngineCoolantTemp".

  • The gateway is able to apply a customer multiplier (x1 in this case) and offset (-40 in this case) to match the requirements of their cloud service.





















Once you have configured your device configuration file, we can update to your FATBOX gateway securely over the air. The gateway HTTPS connected web console must be accessible, if you do not have an Internet connection, you can follow the alternative steps here). 

Log into the G3 (the default address is and enter in the user name and password. Go to the <Management> tab in the G3 web configuration menu. Enable the SSH option (see below) and click the 'UPDATE' button to save your settings. Then reboot the gateway.


Then log in again, go to the <IOT Hardware> menu to set the CAN bus mode to "Query mode" and register the polling configuration as required by the user. Click 'UPDATE' to save your settings. 

(Note that all other interfaces like Modbus and Zigbee can also run concurrently).


Next, click “Upload iotasset.txt” button and in the new window, use the 'CHOOSE FILE' tab to select the above prepared file from your local folder to to send over to G3After the upload is successful you will need to close the page and log in again for security purpose. The user can also confirm the status of iotasset.txt file upload by clicking on Diagnostics::Check File.

We will now also configure the gateway's CAN BUS baud rate. Go to the <Port Settings> tab and enter the following settings below. Once you are done click the 'UPDATE' button to save your settings.


After these settings are updated, REBOOT the gateway. The user can then check the CAN BUS vehicle data collected (Diagnostics::JSON Data) or delete for testing.


Connect to AWS IoT Cloud Service

Now that the connectivity between the ECU Simulator and the G3 gateway has been set, we will then look at getting the data onto a designated cloud service. We support an open customer software and 3rd party API (e.g. REST API for HTTP, HTTPS and MQTT) integration to connect to a chosen cloud data or dashboard service (or to use for on board data processing).

 Direct deployment on Azure, AWS IoT or Ubidots can also be done as these IoT clients have been integrated on the G3 Gateway. For this project, we are going to showcase using AWS IoT
(note that an AWS
account is required to continue this tutorial).

1. Create a new AWS IoT Thing

First log into your AWS IoT Management Console and create a Thing:

AWS IoT > Manage > Thing > Create

Next go to:

Secure > Certificates

Then download the 'Certificate' & 'Private Key File'.

Ensure the Certificate is "Active", otherwise activate it under ACTIONS in 

Things > Your Certificate > Security

AWS Certificate Download.png
2. Update your G3 IoT Gateway
Create a new local folder and name it "AWS". 

Save the downloaded certificate files into this folder and rename them as the following:



Next zip the folder (ensure that you zip the entire folder and not just the files inside).

Then log into your FATBOX G3 web console and go to the <Management> tab.

Patch the zipped folder to the gateway using the UPDATE FIRMWARE button.

3. Create a Security Policy for your Thing

In your AWS IoT Management Console go to:

Secure > Policies > Create

Create AWS Policy.png
At <Things>, select your new Thing then click on

Security > Certificates > Policies

Under <Actions>, choose to Attach a Policy:

Attach AWS Policy.png
4. Configure your G3 IoT Gateway to send data to your AWS Account

Now, you are ready to configure your gateway to send AWS IoT endpoint to feed data to your AWS applications. In the FATBOX G3 web configuration menu, go to the <IoT Client> tab and configure your AWS client settings according as per your AWS end point and Thing settings. Then REBOOT your gateway.

Next go back to go your AWS IoT console and subscribe to the Topic to "Test" that data is being received.

Congratulations! You have succesfully sent your Modbus or CAN bus data to your AWS IoT endpoint and ready to, for example, push the data to a S3 bucket using a Rule in 'Act > Rules'.
The FATBOX G3 AWS IoT client side is built using AWS IoT Device SDK for Python and users are free to install, modify our device client codes for enhanced edge capabilities or other required functionalities.

See our guides below for connecting to other supported IoT platforms includes Azure IoT and Ubidots. Here is a sample dashboard from Ubidots. 


Guides to connect other Cloud Platforms

Connecting to Microsoft Azure IoT Hub

Connect to Ubidots IOT Platform

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