Vehicle-mounted fault diagnosis device

The invention belongs to the technical field of vehicle-mounted diagnosis, and particularly relates to a vehicle-mounted fault diagnosis device which comprises a lower shell, a fixing groove used for positioning and connecting a T-shaped block is formed in the lower shell, the lower shell is connected with an upper shell through the fixing groove, and first sliding grooves used for moving a sliding plate are formed in the two ends of the lower shell. The lower shell is connected with a sliding plate through a first sliding groove, heat dissipation holes used for heat dissipation are formed in the sliding plate, through the arrangement of fixing screws and T-shaped blocks, the fixing screws are fixed to positioning grooves through connecting plates, the T-shaped blocks are fixed through fixing grooves, and through the arrangement, the lower shell and the upper shell can be rapidly assembled and disassembled; the interior of the equipment is convenient to overhaul and replace, the maintenance efficiency is impr