2021 Audi A7 Engine Problems

While driving on the freeway at approximately 65–70 mph, the engine suddenly stopped responding to all accelerator pedal inputs. The vehicle experienced an immediate, dangerous loss of motive power in active traffic. The dashboard displayed an amber check engine light alongside the central master warning light (an amber triangle with an exclamation point inside). I was forced to coast across active lanes of highway traffic to reach the right-hand shoulder. A State Trooper was on the shoulder and approached me, but there was no formal report. After turning the vehicle completely off and waiting, the system temporarily reset, and throttle response returned. The following day, the exact same sudden loss of accelerator response occurred while driving in local traffic, again creating a severe risk of a rear-end collision. The vehicle has been taken to an authorized Audi dealership for a diagnostic evaluation. No diagnostic trouble codes (DTCs) have been provided by the dealer yet. There was no crash or injury, but the sudden, repetitive loss of propulsion on a high-speed roadway constitutes an extreme safety hazard. I am the original owner and have maintained all scheduled maintenance intervals.

At approximately 43,044 miles, my 2021 Audi A7 55 TFSI e quattro (PHEV) was diagnosed with a failed N632 coolant changeover valve — a component of the PHEV thermal management heating circuit. The vehicle has a complete, documented service history with no maintenance gaps. The N632 is an electronically controlled valve that routes coolant between the combustion and hybrid/electric circuits and is essential for cabin heating in EV mode, battery pre-conditioning, and engine warm-up. Failure of this valve can result in loss of cabin heat, coolant leaks into the engine bay, and potential cascade of electrical faults if coolant migrates into the wiring harness. The repair estimate is $1,700. The factory warranty, Audi Care plan, and third-party extended service contract (United Car Care Protection Plus) have all denied coverage. This failure on a low-mileage PHEV with full service history suggests a premature component defect in Audi's PHEV thermal management system. I am requesting NHTSA investigate whether this constitutes a pattern of failure across 2021 Audi PHEV vehicles.

The first time, while driving at 50-55mph, the engine decelerated suddenly. After about 10-15 seconds struggles with the gas pedal and brake pedal, the car accelerated normally. I pulled safely to side of the road to shut off the engine and start again. Things seemed to work like normal. The control panels did not show any warning signs. The second and third times (couple weeks later), while driving around 40-45mph, the engine decelerated suddenly again. After some struggles like I did the first time, the engine accelerated like normal. Like the first time, the control panels did not display any warning signs. I took the car to the Audi dealer garage and they couldn't identify the problems. They performed two "engine software updates" and said hopefully it should address the engine decelerate issue. I was charged $299 for the diagnostic tests. I am worried what would happen if I was driving on a busy and highspeed Freeway!

Water pump design failure caused a leak of coolant into vacuum lines preventing coolant from cooling engine and causing immediate overheating. Known issue previous class action lawsuit.