# 4.1 | Connecting to the COMMAND ECU

To access **COMMAND** ECU settings, enter the **Settings** menu and select the **COMMAND** tab.

The Machine page is used to setup the connection between T3RRA software and the **COMMAND** ECU in addition to selecting the machine profile being used. To get to this page, first go to the [COMMAND Settings](https://docs.t3rra.com/books/level-command-manual/page/42-command-settings "COMMAND Settings") page and click the top left '**Machine**' button.![image.png](https://docs.t3rra.com/uploads/images/gallery/2026-10/scaled-1680-/S5wimage.png)

## ECU Serial Connection

Begin by connecting to the **COMMAND** ECU using the Comms tab. Select the correct COM port from the list OR

Click the '**Scan ports**' button to search for **COMMAND** data among all serial ports present. If the ECU is detected successfully, click **Connect**.

[![image.png](https://docs.t3rra.com/uploads/images/gallery/2026-10/scaled-1680-/26Vimage.png)](https://docs.t3rra.com/uploads/images/gallery/2026-10/26Vimage.png)

[![image (28).png](https://docs.t3rra.com/uploads/images/gallery/2026-10/scaled-1680-/image-28.png)](https://docs.t3rra.com/uploads/images/gallery/2026-10/image-28.png)

#### Connection Failure

If T3RRA Software fails to connect to the ECU over the chosen COM port, a warning will be displayed. Verify power and communication connections before retrying.

#### Successful Connection

[![image (27).png](https://docs.t3rra.com/uploads/images/gallery/2026-10/scaled-1680-/image-27.png)](https://docs.t3rra.com/uploads/images/gallery/2026-10/image-27.png)

Once connected to the ECU successfully, T3RRA Software will:

- Establish communication with the ECU
- Read stored parameters
- Load the current machine configuration