Expire is not really the right term; but effectively yes. In general a cheque older than six months will be considered stale-dated and will not be honoured. Reference the Canadian Payments Association FAQ.
SKYACTIV is a brand name for a series of technologies developed by Mazda which increase fuel efficiency and engine output. The initial announcement of the SKYACTIV technologies include new engines, transmissions, body, and chassis, which appeared in Mazda products from 2011.
All New 2015 Mazda3. With increasing integration of their SkyActiv technology, new engine innovations, and a significant boost in fuel efficiency, the 2015 Mazda3 has become a formidable opponent in the compact sedan class.