As of 684, he was serving as imperial censor reviewing central government affairs (左肅政大夫), when he and his subordinate, Yu Chengye (魚承曄), was put in charge by Emperor Ruizong's powerful mother and regent Empress Dowager Wu (later known as Wu Zetian) of investigating and interrogating the chancellor Pei Yan after accusations of treason, as Pei had angered her by suggesting that she return imperial authority to Emperor Ruizong.
She also made him acting Neishi (內史) -- the head of the legislative bureau of government (鳳閣, Fengge) and a post considered one for a chancellor.
Another chancellor, Liu Yizhi, instead stated, "You were dragged into this because of another's fault, and your demotion was based on the decision of the officials."
Winter of that year, he was made chancellor again, this time with the designation of Tong Fengge Luantai Pingzhangshi.
However, he was soon falsely accused of unspecified crimes—and Empress Dowager Wu gave the case to Qian's subordinate Zhou Ju (周矩) for investigation.