By Samuel Shen and Norihiko Shirouzu
SHANGHAI, March 14 (Reuters) - German carmaker BMW said on Friday it will recall an unspecified number of vehicles proactively in China after months of consumer complaints over a potentially defective engine control component.
BMW said in a statement released via the Sina Weibo microblog that it had started a "full investigation" into a potential bolt problem with VANOS -- a device used in BMW engines that controls air intake and exhaust valves.
BMW's announcement comes a day before China's Consumer Day on March 15 which has in previous years spotlighted local and global brands over quality issues.
"BMW pays high attention to the recently reported VANOS bolt issue," said the statement. The statement did not describe the nature of the defect or specify how many cars are affected.
"We will file our recall application to the AQSIQ as soon as possible," it said, referring to China's quality watchdog, the General Administration of Quality Supervision, Inspection and Quarantine.
It also did not say whether the recall is going to be confined to China or whether it could potentially affect BMW cars in markets elsewhere.
A BMW spokesman in Beijing declined comment.
It's highly unusual for carmakers in China to disclose recall plans ahead of official recall announcements by regulators.
As part of China's Consumer Day, every year a TV program called "3.15," produced by the China Central Television (CCTV), exposes consumer neglect in China by local and global consumer brands. Past targets have included Apple Inc and carmaker Volkswagen AG.
Last year's program highlighted Volkswagen. Shortly after the show aired, the German automaker recalled 384,181 vehicles in China to replace defective gear boxes.
BMW's announcement -- issued by BMW (China) Trading Automotive Ltd, which imports BMW cars into China, and BMW Brilliance Automotive Ltd, the Chinese joint venture that manufactures BMW vehicles locally -- followed months of complaints by groups of BMW car owners about what they described as BMW's quality issue with the VANOS system.