Which of the following should be the first step in diagnosing an engine performance concern? Retrieve diagnostic trouble codes Discussing concern with the vehicle owner Check for symptoms in the on-line service manual Road test the vehicle

The first step in diagnosing an engine performance concern should be to discuss the concern with the vehicle owner. This will provide valuable information about the symptoms and any error codes that may have been displayed. Once this information is gathered, the technician can then proceed with the other steps such as retrieving diagnostic trouble codes, checking for symptoms in the on-line service manual, and road testing the vehicle.