A7 Power Loss Alert: DIY vs Pro Diagnostics Guide

Had a similar situation with my 2017 Audi S5 after getting it chip tuned at a third-party shop. The engine issue started with power loss and constant engine light warnings. Vehicle diagnostics revealed the tune was incompatible with the engine control module. The repair required a complete reset of the ECU and removal of the problematic tune. A factory-authorized diagnostic scan showed multiple fault codes related to boost pressure and fuel mapping. This was a serious issue that could have led to engine damage if left unchecked. For your A7, the symptoms suggest possible tune-related problems. These dashboard light warnings should not be ignored. Using a generic car diagnostic tool might help identify basic codes, but Audi-specific vehicle diagnostics are recommended for accurate results. The safest approach is having an authorized dealer perform a full diagnostic code scan. They can determine if unauthorized tuning is causing the power loss and properly reset the system. This prevents potential long-term engine damage and preserves warranty coverage if applicable. Main takeaway: Power loss combined with warning lights often indicates software or tuning issues that require professional diagnosis with proper equipment.

Thanks for sharing your S5 experience. That reduced power issue sounds exactly like what I am experiencing with my A7. The check engine light started flashing last week and the car feels significantly weaker, especially when accelerating. Did you get your car computer fully reset at the dealer? I am considering buying a basic diagnostic scanner to read the fault codes myself first. But wondering if it is worth the investment or should I just go straight to a certified shop. Also, can you remember roughly how much you paid for the diagnostics and fix? Have you had any similar issues since the repair?

Had to update on my previous post: I took the car to a certified shop last month, and they found the exact issue using their professional diagnostic equipment. The fault code detected was related to unauthorized chip tuning, just as I suspected. The car computer needed a complete reset and proper recalibration. The total repair cost was 180 Euro, which included the diagnostic scan and ECU reset. Since fixing the faulty chip tuning, the car has been running perfectly with no power loss issues or warning lights. The engine response is back to normal, and fuel consumption has actually improved. If you are seeing similar symptoms, I would skip the basic auto scanner route. These third-party tuning problems often require specialized diagnostic tools to properly identify and fix. The shop's professional equipment detected multiple fault codes that a basic scanner might have missed. Getting it fixed properly the first time saved me from potential long-term engine damage. As a side note, the car computer reset completely removed all traces of the problematic tune, returning the vehicle to factory specifications. No engine issues have occurred since the repair was completed.

Thanks for the helpful advice. Following your suggestions, I went ahead and took my A7 to a certified shop this week. The scan tool they used picked up multiple fault codes, and turns out my car had an unauthorized tune from the previous owner that was causing the power loss. The total fix came to 250 Euro which covered the vehicle diagnostics and a complete ECU reset. More than I wanted to spend, but worth it since the car runs perfectly now. The engine issue is completely resolved, no more warning lights and power delivery is smooth again. Glad I skipped buying my own auto scanner and went straight to professionals. Their diagnostic equipment caught additional problems I would have missed with a basic tool. The engine feels much more responsive after the repair and I have better fuel economy too. Really appreciate all the guidance. Lesson learned about the importance of proper car computer diagnostics when dealing with modern vehicles.