RS5 Rail Pressure Sensor Causing Stalls & Power Loss

Had similar issues on a 2012 S5 last month. The symptoms match exactly what you describe, stalling at idle, check engine light, and reduced power output. The fuel pressure sensor on the fuel rail was indeed the culprit. In my case, the faulty sensor was causing incorrect readings, making the fuel injection system run either too rich or too lean. The engine management system was getting confused by these false readings, leading to the performance issues. This is a relatively straightforward fix but requires proper diagnostic equipment. The sensor itself is integrated into the fuel rail assembly on many Audi models. While it might seem tempting to just replace the sensor, often the complete fuel rail needs replacement to ensure proper function. The most important thing is having a shop that knows how to properly bleed the fuel system after replacement. Incomplete bleeding can cause ongoing issues with fuel pressure regulation. This is not a repair you want to postpone, as incorrect fuel pressure readings can potentially cause serious engine damage over time. The reduced power output you are experiencing is actually a protective measure by the engine management system. Make sure the shop performs a full system diagnostic before replacement, as similar symptoms can sometimes be caused by fuel pump issues or wiring problems in the fuel injection system.

Thanks for sharing your experience. Our symptoms do sound identical, the stalling and engine performance issues were really concerning. Did you remember roughly what the total repair cost was for your fuel rail pressure sensor replacement? Also curious if you have had any recurring issues with the fuel injection system since the fix was done. Just trying to get a better idea what to expect with my RS5 showing similar problems.

Just an update on my earlier post, got the rail pressure sensor issue fully resolved last month. Total cost came to 240 Euro for the repair, which included replacing the defective pressure sensor and complete system diagnostics. The fuel injection system has been working flawlessly since the fix. No more engine stalling or power loss issues. The check engine light cleared up immediately after the repair and hasnt come back. What made the difference was finding a shop that properly diagnosed the fuel pressure problem. They confirmed the faulty sensor was sending incorrect signals to the engine management system, causing the erratic performance. The repair eliminated all the symptoms, the unusual stalling at idle, poor engine performance, and irregular fuel pressure readings are completely gone. If your RS5 is showing these same signs, getting that pressure sensor checked should solve your issues too. Worth mentioning that proper fuel system bleeding after the repair is crucial. Make sure your mechanic includes this in the service, as it helps prevent any recurring diesel engine performance problems.

Thanks for the helpful advice. Finally got my RS5 fixed last week and wanted to share the outcome. Took it to a specialized shop that properly diagnosed the fuel pressure issue. The rail pressure sensor was indeed bad and needed replacement. Total repair came to 280 Euro including parts and labor. The mechanic showed me the diagnostic readings before and after, the sensor signal was all over the place initially. After replacement, the fuel injection system is working perfectly again. No more stalling, full power restored, and the check engine light is gone. They did a complete fuel system bleed as part of the service. The whole repair took about 3 hours. Really glad I got this sorted quickly based on the feedback here about potential engine damage from wrong fuel pressure readings. The car runs like new now, smooth idle and proper acceleration. Should have done this sooner instead of worrying about previous bad experiences with mechanics. Sometimes you just need to find the right shop.