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.
Toyota and Mazda officially announced their strategic partnership in mutual sharing technologies today. The two Japanese companies will benefit from smaller development costs with Toyota said to share its plug-in hybrid and fuel cell technology and Mazda to allow the use of its Skyactiv engine range as the first step of the agreement.