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.
For the third consecutive year, Mazda has achieved the highest fuel efficiency of any other mainstream automotive manufacturer in the industry, without offering a hybrid or electric vehicle. Mazdaâs unique SKYACTIV Technology has made this level of efficiency possible.