| Error Message | Likely Cause | Solution | | --- | --- | --- | | “Communication Failed” | Wrong COM port, cable not detected, radio off | Check Device Manager; try a different USB port; reboot PC. | | “Codeplug Too New/Too Old” | CPS version mismatch | Find a newer or older version of the CPS that matches the radio’s firmware. | | “Checksum Error” | Corrupted codeplug | Write a known good codeplug from a working radio or have the radio serviced. | | “Invalid Frequency” | Frequency outside radio band split | Check your GP338’s model number (e.g., VHF: 136-174 MHz, UHF: 403-470 MHz or 450-527 MHz). |
While originally built for older systems, many versions are compatible with Windows 7, 8, 10, and 11 2. Hardware Setup motorola gp338 programming software