China's Yutu (Jade Rabbit) moon rover has experienced a "mechanical control abnormality", prompting scientists to organise an overhaul, the state media agency Xinhua has revealed.
The malfunction was blamed on the "complicated lunar surface environment". The problem emerged just before the rover was to enter its second dormancy at lunar night, Xinhua reported.
Chang'e-3 probe's lander, another part of the moon roving mission, "fell asleep" hours before Jade Rabbit malfunctioned.
The lander and the rover had been dormant for two weeks over the first lunar night of the mission, when the solar panels cannot recharge.
Jade Rabbit was separated from lander on 15 December, hours after the Chang'e-3 probe landed on the Moon's Sinus Iridum, or the Bay of Rainbows.
The rover is equipped with a panorama camera, a particle X-ray and infrared imaging device and radar through which it obtains scientific data.
As the first dormant stage passed, the lander's ultraviolet camera observed the plasmasphere over the Earth, according to China's State Administration of Science, Technology and Industry for National Defence.
The Chang'e-3 probe makes China the first country to successfully accomplish a soft landing on the lunar surface since the former Soviet Union's mission in 1976, and the third country to send a lunar rover to the moon after the US and the USSR.
The rover was to survey the moon's geological structure and look for natural resources for three months, while the lander was assigned to conduct in-situ exploration at the landing site for one year.
Both the rover and the lander have performed well until now, enduring temperatures that reached -180°C during the previous lunar night.