If the passport is expiring soon, you should renew it and inform IRCC by sending a scan of the passport. This will help you in tow ways.
1. The PR visa is usually not issued beyond the validity of the passport. If the passport is expiring soon, the visa validty will be limited.
2. If the passport expires after you move to Canada, you will have to go through all the hurdles of getting it through your country's embassy, and it may be much easier to have it done in your current country of residence.