During exploitation motor vehicles require a number of maintenance, repair and diagnostic activities. Among all road vehicles, buses deserve special attention. These vehicles are designed to transport more than 9 people with the driver. Contemporary buses are characterized by a significant number of inseparable - adhesive joints. At the production stage the assessment of the quality of adhesive joints can be carried out using destructive and non-destructive methods. The assessment of the quality of adhesive joints of new vehicles can only be carried out using non-destructive methods. Adhesive joints of steel profile-plywood used in modern buses, is a combination difficult to test joints. Such combination can not be examined using classical control techniques. The article proposes not only the use of a surface ultrasonic wave, but also the possibility of analysis of the obtained signals in the frequency domain using the Fast Fourier Transform (FFT). The tests confirmed that within a certain range, this approach allows the assessment of the width of the adhesive path in adhesive joint.