WARNING: This page is about a different car, the 2004 Suzuki Aerio, 2003 Suzuki Aerio, and 2002 Suzuki Aerio. However, it is still accessible from the selected car via links, so may be relevant.
Check boot for crack and damage which, if any, means possibility of rusty gear, entry of dust or lack of grease. Also, check if any of such faulty conditions exists.