I finally managed to resolve my text messaging issue so thought I’d share it here:

Provider: Koodo
Phone: Motorola W385

Issue: Could not send text messages. Was able to receive. Error message “Failed to send”

Resolution:
1. Dial *22803
2. Select 1 for English
3. Select 2 for upgrade PRL (Preferred Roaming List)

Alternate Resolution:
I didn’t try this but apparently if you know your Service Code you can go to:
Koodo Programming Instructions for the W385