This means that Yuchai's YC6J series engines (pictured) is now one of the five major Euro IV engine systems recognized by the European Union (EU). Yuchai is China's first heavy-duty diesel engine manufacturer to receive this certificate.
In China, OBD systems were adopted in all National III (a Euro III emission standard equivalent) compliant light-duty vehicles. After the roll-out of National IV standards, the city of Beijing is now requiring all new medium and heavy-duty vehicles to install this system, which issues a warning if a certain emission limit is exceeded through an on-board system monitoring of the automotive exhaust system.
[Source: China Yuchai]