What is a common tool used for diagnosing frame misalignment?

A frame straightening machine is specifically designed to diagnose and correct misalignment issues in vehicle frames. This tool uses precise measuring systems and hydraulic force to assess the structural integrity of a vehicle's frame. It allows technicians to determine the extent of the misalignment and apply necessary adjustments to restore the frame to its original specifications. Frame straightening machines typically include features such as laser measurement systems or alignment fixtures that help in accurately diagnosing any deviations from the manufacturer's design.

The other tools mentioned serve different purposes: a compression tester is primarily used for examining engine cylinder compression, a multimeter measures electrical parameters such as voltage and current, and a brake gauge is utilized to check brake system efficiency and alignment but is not tailored for frame diagnostics. Thus, the frame straightening machine stands out as the most appropriate tool for identifying and correcting frame misalignment.