In order to prevent unnecessary airbag deployments, many cars are equipped with a passenger detection system that can disable the passenger-side front airbag in the event there's nobody seated there. If that system goes wrong, the consequences can be dire, which is the reason for Audi's latest recall.
Audi recently issued a recall for 144,000 examples of its vehicles. This group includes the 2017-2018 Audi A4/S4 (sedan and Allroad variants) and the 2018 Audi A5/S5 (in coupe, convertible and Sportback variants). The recall population covers the aforementioned vehicles with build dates from their respective starts of production until July 31, 2018.
The issue comes from the passenger detection system that's linked to the passenger airbag. The cable has a self-diagnosing function that is apparently too sensitive. If the cable's shielding has even partial surface oxidation, the detection system will malfunction and disable the passenger airbag, even though a passenger might be seated there. If this happens, the "passenger airbag off" will illuminate as expected, in addition to the airbag warning light. This defect can result in an increased risk of injury in a crash.
Audi first caught wind of the issue in mid-2017, when it received an increased number of field reports about passenger-detection-system replacements. In conjunction with its supplier, Audi dug into the data and eventually discovered the reason behind the fault. While the company is still working to find out why the issue develops and why certain vehicles are apparently more susceptible to it, Audi initiated a recall.
The fix is relatively straightforward, sort of. Audi technicians will take recalled vehicles and apply a software patch that adjusts the diagnostics' thresholds, preventing the cable oxidation from disabling the passenger airbag. However, it has not yet issued a correction in production and is still evaluating that side of things. Owners should expect to receive recall notifications by mid-September.