Sound energy belies an enormous amount of information which can provide assistance in various applications like navigation, communication, recognition, medical - diagnosis, detection and therapy, analysis & design of structures and many more. This paper presents a method for detecting faults in car engines just by recording their sounds through window based applications in mobile phones and processing it in the mobile phone using our algorithm. The algorithm preprocesses the sound to remove the noise if present, the noise free car engine sound is passed through a triangular window to acquire the Multi resolution coefficients for discrete wavelet transform and compare resulting plots. The Wavelet transform analysis is done and the plots are scrupulously analyzed and the faults can now be detected by referring to plots. With a little know-how non technical persons can now detect the abnormalities in car engines just be using this automation.