Audi A4 Massage Seat Malfunction, Diagnosis Guide

Having some experience working on Audis, I faced a similar massage seat switch failure in my 2020 A6 last year. The symptoms were identical, complete loss of massage function and an error code. The issue turned out to be a loose cable connection at the seat control module. The workshop diagnosed it by checking the wiring connectivity between the massage seat control unit and the main switch. After running diagnostics, they found that the connection had worked itself loose over time. The repair involved removing the seat trim, accessing the control module, and securing the cable connection properly. Total cost was 95 Euro including diagnostic work. Since the fix, the massage function has worked flawlessly. To help diagnose your specific case, could you share: Does the seat adjustment still work normally? Are there any other electrical issues with the seats? Which error code is stored? Did the problem start suddenly or gradually? This information would help determine if your A4 is experiencing the same connection issue or if its a different massage seat component causing trouble.

Last service was done at 50000 KM and the massage function worked fine until last week. The seat adjustment and heating functions are working perfectly, only the massage feature is affected. The error code shown is B138742. The issue started quite suddenly after a long highway drive. Given that others have faced similar automotive seats issues, I will get the wiring connections checked. The car upholstery will need to be partially removed to access the control module, so I want to be certain before booking a workshop appointment.

Thanks for providing those details. Since I dealt with the same massage setting issue on my A6, I can confirm that the symptoms match my experience almost exactly. The error code B138742 typically points to a communication fault between the seat control module and the massage components. The fact that your seat adjustment and heating work normally actually strengthens the loose connection theory, since these functions use different circuits than the massage feature. The sudden onset after highway driving is also consistent with my case, vibrations can gradually affect connector security in luxury car seat wiring. When the workshop fixed my automotive seats, they mentioned these connection issues are relatively common in this model line. The massage seat switch itself is usually not the culprit when other seat functions remain operational. Before you book the appointment, one quick check you can try: press firmly on different areas of your seat while attempting to activate the massage function. If you get even a momentary response, it almost certainly confirms a loose connection rather than a failed massage seat switch or control module. Expected repair costs should be around 100 Euro to 150 Euro if its the same wiring issue I experienced. The job typically takes about an hour once they get the seat trim removed.

Based on your detailed feedback and similar experience, I feel more confident about the diagnosis now. I will schedule an appointment to have the car upholstery removed and the wiring connections inspected. The consistent symptoms between our cases, especially how other seat functions work fine while only the massage feature is affected, makes me think this should be a straightforward fix. Good to know the repair costs should stay under 150 Euro. My luxury car is still under warranty, but I will check if this type of massage seat wiring issue is covered. The fact that these connection problems are somewhat common in the model line is useful information. I tried the test you suggested, pressing on different areas while attempting to activate the massage function, but got no response. Still, since all signs point to a wiring issue rather than a failed component, I will proceed with having the automotive seats checked at the workshop. Will update once its resolved.