Audi S4 Diesel Boost Sensor Causes Multiple Failures

Having experienced identical symptoms with my 2016 Audi A6 3.0 TDI, this sounds exactly like a boost pressure sensor failure combined with a loose connection. The check engine light repeatedly activated during acceleration, especially when the turbo boost was needed most. The whistling noise typically indicates a boost leak, while the jerking and high fuel consumption point to the engine running in safe mode due to incorrect pressure sensor readings. The intake manifold pressure sensor plays a crucial role in regulating fuel mixture, and when it fails, the engine management system gets confused. The fix required checking the wiring harness where it connects to the pressure sensor. In my case, the connector had corroded and was making intermittent contact. The mechanic cleaned the connection points, replaced the boost pressure sensor, and performed a complete diagnostic reset. This is a serious issue that needs immediate attention as it can lead to engine damage if left unchecked. The engine constantly trying to compensate for incorrect readings puts additional stress on various components. The complete repair should include testing all related sensors, checking intake manifold connections, and verifying turbo boost functions properly after the fix. The stalling at idle is particularly concerning as it suggests the engine management system is receiving inconsistent data from the faulty sensor.

Thanks for sharing your experience. Dealing with similar turbo system issues on my S4 last year. The symptoms you described match exactly what I encountered, engine light, jerking, and that distinct whistling noise from the boost leak. Quick question, do you remember the total repair cost for the sensor replacement and diagnostic work? Also, has everything been running smoothly since the fix or have you noticed any other turbo boost related problems? Its important we track these issues since faulty boost sensors seem fairly common on these models, especially around that mileage.

The repair ended up being much simpler and cheaper than expected, just 95 Euro to fix a bad connection at the boost pressure sensor. When I took it back to the mechanic, they discovered the pressure sensor itself was actually fine. The real culprit was a loose plug connection that was causing intermittent signal issues to the engine management system. Since fixing that faulty cable connection, the air intake system has been working perfectly. No more check engine lights, the whistling noise disappeared completely, and fuel consumption returned to normal. The turbo boost now builds smoothly without any jerking or hesitation. The mechanic also performed a full diagnostic scan after the repair to ensure there were no lingering issues in the intake system. Been driving it for several months now without any boost leak symptoms or pressure-related problems returning. Looking back, the early warning signs like inconsistent boost pressure readings and engine performance issues were classic indicators of a connection problem rather than a complete sensor failure. This kind of issue seems quite common in these engines once they get some miles on them.

Thanks everyone for the helpful input. After reading about similar experiences, I finally got my S4 properly diagnosed. Turns out my problem was indeed boost related, but slightly different than expected. The mechanic found a small crack in the intercooler pipe causing a significant boost leak. They also discovered a loose connector at the turbocharger pressure sensor, which explained the erratic readings. Total repair came to 280 Euro including parts and labor. The fix completely transformed the car. No more check engine light, the whistling noise is gone, and acceleration is smooth again. Fuel consumption dropped back to normal levels too. Really glad I got it sorted before any serious engine damage occurred. Worth noting for others, the initial diagnosis at another shop missed these issues completely. Finding a mechanic who really knows turbo systems made all the difference. The car runs better than it has in months.