WARNING: This page is about a different car, the 2003 Mitsubishi Outlander. However, it is still accessible from the selected car via links, so may be relevant.
Hold the camshaft sprocket with special tools MB990767 and MD998719.
Fig 1: Holding Camshaft Sprocket With Special Tools MB990767 And MD998719
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Loosen the camshaft sprocket mounting bolt and remove the camshaft sprocket.