Diesel particulate filters (DPF) require routine cleaning to remove ash that builds up over time. Most vehicles using a DPF system will have an on-board filter service monitor to indicate the filter condition and guide your filter cleaning schedule.
In ancient times the islands formed an independent kingdom. Chinese and Japanese sovereignty were successively forced on the archipelago from the 14th to the 19th century, and in 1879 the Ryukyus became an integral part of Japan. After the defeat of Japan (1945) in World War II, the United States took control of the islands.
All the large cities (with the exception of Kyoto), the industries and the transportation networks were severely damaged. A severe shortage of food continued for several years. The occupation of Japan by the Allied Powers started in August 1945 and ended in April 1952. General MacArthur was its first Supreme Commander.