FAILURE DIAGNOSIS METHOD AND FAILURE DIAGNOSTIC DEVICE

PROBLEM TO BE SOLVED: To provide a failure diagnosis method and a failure diagnostic device which allow an operator with little experience to easily perform fault diagnosis while promoting the operator's accurate judgment and improving his/her skill level.SOLUTION: In a failure diagnostic device 16 and a failure diagnosis method, a failure code is read out from an ECU 20 to the failure diagnostic device 16, and an operation guidance screen 110 for guiding an operation in response to the read failure code is displayed. The operation guidance screen 110 includes an overall operation display area 114 which includes an overall operation flowchart 120 comprising multiple operation items for identifying a failure occurrence place where a failure event corresponding to the failure code is generated and highlights an item selected from the multiple operation items, and a concrete operation display area 116 which shows a concrete operation content on the highlighted operation item.