The loonie ended the session at 89.02 cents US.
The interest rate meeting of the U.S. Federal Reserve is the major event as markets will be curious to see if the Fed decides to postpone the end of a key stimulus program, its massive purchases of bonds.
The Fed has been winding down the program, which has kept long-term rates low and fuelled a strong rally on stock markets.
There has also been a high degree of speculation about when the Fed might raise interest rates once the so-called quantitative easing ends. Markets generally have expected a Fed interest rate hike sometime in 2015, with sentiment pointing to mid-year if the bond buying program ends this month.
"As global growth fears took hold, the expectations shifted and were pushed out until late 2015 — now these are being pulled back in, sitting at October 2015 for the first (rate) hike," said Camilla Sutton, chief FX strategist, managing director, Scotiabank Global Banking and Markets.
Traders also looked ahead to the first reading of third-quarter gross domestic product in the United States and August GDP data for Canada.
On the commodity markets, December crude dropped $1.08 to US$81.01 a barrel, while December copper was unchanged at US$3.04 a pound and December gold bullion rose $2.70 to US$1,231.80 an ounce.