When you use the Cat Comm Adaptor 3 to connect your PC to a Caterpillar machine, the Cat ET software may display various error codes. Below is a list of common error codes and their solutions.

| Error Code | Error Description | Possible Solutions |
|----------------|---------------------|---------- ----------------|
|Initialization file does not exist. | Install the Cat Communication Adaptor II software on the PC and reboot. |
|Unable to read Cat Communication Adapter (RP1210) initialization file. |Restart your computer. If the problem persists, reinstall the Cat Comm Adaptor 3 software and reboot after installation. |
| CA2RP32.DLL could not be loaded. Restart your computer. If this does not work, reinstall the Cat Comm Adaptor II software and reboot after installation. |
| 142* |The interface hardware is not connected. Check all cables to make sure they are connected properly. Make sure the "power" light on the Cat Comm Adapter II is on and that your Cat electronics technician has set it to the correct comms port.|
| 202 |Required INI file not found. Uninstall and reinstall the Cat Comm Adaptor 3 software and reboot.|
| 204 |Required INI file key not found. Uninstall and reinstall Cat Comm Adaptor 3 software and reboot.|
| 205 |A required INI file key was not found. Uninstall and reinstall Cat Comm Adaptor 3 software and reboot.|
| 206 |A value in the INI file was invalid. Uninstall and reinstall Cat Comm Adaptor 3 software and reboot. |
| 230 | Port not open. Another program or device is using the communications port. Determine the source of the conflict and disable it or switch to a parallel port if possible. |
| 231 | Invalid communications port. Make sure the selected port is configured correctly in your PC's BIOS or operating system. |
| 301 |Unable to open configuration file. Uninstall and reinstall Cat Comm Adaptor 3 software and reboot. |
| 302 |Session identifier not found in configuration file. Uninstall and reinstall Cat Comm Adaptor 3 software and reboot. |
| 303 |Configuration file was malformed. Uninstall, reinstall and reboot the Cat Comm Adaptor 3 software.|
| 405 | There was a problem with the communication baud rate setting on your PC. Power off and on the Comm Adaptor 3 and reboot your PC. If the problem persists, try lowering the baud rate.|
| 406 |A problem occurred during the initialization phase. See the specific error code (142, 405, 441, or 453) for more information.|
| 441 |The requested protocol is incompatible with the existing data connection. Power cycle the Cat Comm Adapter II and ECM and reboot the PC. Do not start the Comm Adaptor 3 Toolkit while Cat ET is running.|
| 443 |The communications adapter driver software and firmware are incompatible. Install the correct firmware for the Comm Adaptor 3.
| 453 |Communication adapter detected but not responding. Use Device Manager to uninstall the COM port and look for new hardware to reinstall. |

This guide will help you troubleshoot common issues with the Cat Communication Adaptor 3.