A Bit About Form 5471

If you are US person and control a Canadian Corporation, the corporation is considered a Controlled Foreign Corporation (CFC).   This triggers filing 
Form 5471, (Information Return of U.S. Persons With Respect to Certain Foreign Corporations) which should be an information reporting return, but can have tax implications.

Form 5471 translates the corporate activity into US terms - US accounting standards (US GAAP) which are used for US tax.

Form 5471:

• Translates the Canadian Balance Sheet
• Translates the Canadian Income Statement
• Identifies where US considers stuff taxable but Canada doesn't.  Subpart F income gets pulled out. 
• For example, if you have a bunch of stuff going on in the company that does not relate to the business such as investments, below market rate loans etc. This income gets pulled out and becomes taxable income (subpart F income) even though the company never distributed the income. 
• Exposes activity between the corporation and yourself - maximum balance of the loan during the year etc.

The form connects the dots between the Canadian activity and US standards which are used for taxes.

All of these articles sound like your house is on fire, but this article does kind of explain it a bit. 
http://www.forbes.com/sites/robertwood/2014/03/03/scariest-tax-form-skip-it-and-irs-can-audit-forever/#7e3091f564f7