A new approach to tracing car noises
By a large margin, the concern that sees more repeat repair attempts (and consequently more repair shop visits) is when a vehicle makes an unusual noise. It's such a headache that automakers often devote entire training sessions and repair manual sections to this one issue.
Czech automaker Skoda (one of the many brands under the Volkswagen Group umbrella) is piloting a unique smartphone app to help customers and technicians get to the bottom of certain noises the first time, leading to much happier customers. The unique software simply requires a tech (or a vehicle owner) to hold their phone close to the engine when it's running.
The sound is picked up by the phone's microphone, converted to a spectrogram, and compared to recordings of a known good engine, which helps narrow down the source of the problem.
The app can also interpret sound patterns related to A/C compressors, steering systems, and transmission operations. According to Skoda, its beta-test rollout has achieved a 90 per cent success rate.
The noise or vibration diagnosis game isn't new. Years ago, Ford introduced a vibration analyzer that combined a series of sensors to pick up a bothersome vibration frequency, which was then entered into their software. This program had enough detail on individual vehicles that it could detect the difference between vibrations caused by a power steering pulley versus an alternator pulley.
Another very popular tool for pinpointing noises is a simple device commonly called “shop ears.” It consists of four or five microphones wired to a small amplifier. The microphones are placed in various areas in or under the vehicle, and the amp is placed inside where a tech can switch from one feed to another during a test drive to help get an idea of where a noise is coming from.
Recording a noise with your smartphone and then playing it back at the service counter won't be of much help, as it leaves out this critical piece of information.
If the noise is intermittent, you're better off waiting until it becomes constant enough to be duplicated by your shop on a road test, or other type of inspection. If it only occurs under certain conditions, ask, when making your appointment, if you can arrange a road test with the technician working on your vehicle. As pandemic restrictions might not make this possible, make detailed notes of all the conditions such as speed, type of road surface, whether you're turning, etc.
Finally, don't confuse a vibration (something you feel) with a noise (something you hear).