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.
Using SKYACTIV on a larger crossover like the Mazda CX-5 allows it to retain capability while raising fuel economy to the level of most passenger cars. Standard for the 2015 Mazda CX-5 is a 2.0L four-cylinder engine producing 155 hp and 150 lb-ft of torque. With this engine, drivers can get up to 35 mpg highway.