Audi S4 Hood Safety System Fault Triggers Airbag Alert

I had a very similar system fault on my 2016 Audi S5 last winter. Having some experience with sensor issues, I first suspected the crash detection system was malfunctioning. The hood latch safety system activated unexpectedly while driving, and the airbag warning light stayed on continuously. The car safety computer showed multiple error codes related to the acceleration sensor. After attempting basic troubleshooting like disconnecting the battery for 30 minutes (which did not help), I took it to a workshop. They diagnosed a defective acceleration sensor that was sending false signals to the safety systems. The repair involved replacing the faulty sensor and recalibrating the crash detection system. Total cost was 315 Euro including parts and labor. To help with your specific case, could you share: Have you scanned for specific error codes? Did this start suddenly or develop gradually? Has the car experienced any recent impacts or been serviced lately? Are there any other warning lights active? This would help determine if your issue is similar to what I experienced or potentially something different in the safety system.

Last service was at 160358 KM and yes, I scanned for error codes with my OBD tool. It showed code B1234 for the hood latch system and U0428 for the collision detection module. The issue started suddenly during normal driving without any impact or accident. No other warning lights are active besides the airbag warning on the dash. The car safety system seems extra sensitive lately, even small bumps trigger the pedestrian safety sensors. I might try the battery disconnect suggestion before taking it to a workshop, but Im concerned about the repair costs if the entire sensor array needs replacement. The hood actuators already deployed once, adding to potential part expenses.

Based on those error codes and symptoms, your situation sounds nearly identical to what I experienced. The hypersensitive pedestrian safety sensors definitely match my case, mine would occasionally trigger from driving over normal road bumps. The good news is that in my case, and likely yours too, the entire sensor array did not need replacement. The core issue was isolated to the main acceleration sensor within the crash detection system, which was sending faulty signals to the car electronics and hood latch mechanisms. While the battery disconnect is worth trying, in my experience it only temporarily cleared the fault before it returned within a few hours. The proper fix required: 1. Replacement of the faulty crash sensor 2. Reset of the hood latch system 3. Recalibration of the pedestrian safety detection system 4. Clearing all stored error codes My total repair costs broke down to: Sensor: 180 Euro, Labor: 135 Euro, System calibration: included One tip: make sure to document all the error codes and symptoms for the workshop. In my case, this helped them diagnose the issue faster and avoided unnecessary parts replacement. Would you like the specific part number for the sensor that was replaced in my car? It might help compare if yours needs the same component.

Thanks for sharing those details about your errors codes and recent service history. Learning the battery disconnect worked temporarily in your case gives me hope this might be a simpler fix than initially feared. The fact both our cars developed identical symptoms, hood latch activation and hypersensitive pedestrian safety sensors, strongly suggests the same root cause. The breakdown of your repair costs is particularly helpful. A total around 315 Euro for parts and labor is much more reasonable than replacing the entire sensor array, which I worried might be necessary after the hood actuators deployed. Since our system fault symptoms match so closely, including the same crash detection behavior, I feel more confident moving forward with repairs. Yes, I would appreciate that sensor part number to reference when discussing repairs with the workshop. Given how the safety system is behaving and those specific error codes appearing, it seems likely I am dealing with the same faulty acceleration sensor issue you encountered. I will attempt the battery disconnect first, but will plan to schedule workshop time if the warnings return as you described.