2021 Audi A6 Allroad problems

“While operating the vehicle under normal driving conditions, the vehicle suffered an immediate, un-commanded loss of engine power and throttle response. The vehicle displayed a critical dashboard restriction stating: “Maximum engine speed 2500 RPM”, forcing an emergency limp-home mode that instantly created a roadway collision hazard. Simultaneously, the vehicle's primary safety and convenience systems dropped completely offline, displaying synchronized, consecutive malfunction alerts for the Central Locking System, Audi Pre Sense (Distance Monitoring), Cross Traffic Assist, and Lane Change/Blind Spot Warning systems. A subsequent professional diagnostic scan confirmed that the vehicle's Engine Control Unit (ECU) has hard-logged active manufacturer fault codes P310A (Low Fuel Pressure Regulation - Fuel Pressure Fluctuates) and P310B (Low Pressure Fuel Regulation - Fuel Pressure Outside Specification). These synchronized electrical and drivetrain failures occur intermittently, yet have specifically occurred multiple times following exposure to moisture, including rainfall, winter slush, and standard car washes. The identical electrical system dropouts were…”

“Car reported an engine restarter issue (with battery symbol) and recommended to contact the dealer. Car next shut down automatic restart system, and air conditioning stopped working. Within a short period of time (same day), the car listed a red battery symbol and advised to stop the car. After doing so and contacting the Audi roadside, the car was listing a series of issues on multiple symptoms while also saying in the warning message "still okay to drive". These systems included steering, braking, and what seemed to be other sensors the car powers. Finally (and within 5 minutes of the previous message of being okay to drive), the warnings were continuous and started including the transmission. The car stopped accelerating (we were on the expressway) and we thankfully got to the side of the road. This was an enormously dangerous situation as the car became fully disabled and we were subject to limited options of relief from a major traffic area. Within 30 minutes of being disabled, no electrical charge was present in the car, including emergency flashers, making the situation more dangerous as it was nighttime, so we had to abandon the car and walk down the…”

“The car has traffic sign recognition and uses it for "predictive control" where the vehicle will read traffic signs and adjust the adaptive cruise control setting to based on road signs. It had previously been working well but a software update was recently performed under TSB 2074688/3 on November 6th, 2025 and problems have shown up. Specifically, the system is incorrectly reading signs and sometimes appearing to make signs up out of nowhere. This has resulted in the car slowing down quickly on highways and nearly causing a couple of rear-end collisions due to the unexpected and erratic braking at highway speeds. The car will be going back to the dealer to be looked at, however this is unsafe because other drivers aren't prepared for a car randomly slowing down in front of them while on the highway for no reason. The car is also available to be inspected if needed. The issues first appeared within a week of having the TSB performed and has happened a number of times since. The following incidents have occurred: * Once on Highway 10 heading North/West between Big Lake and Elk River MN; the car was set to 60mph and hallucinated a 15mph speed limit sign. There…”

“Audi has failed to come up with a repair for recall 22V742. My car consistently shows 1/4 tank of fuel when it’s actually near zero.”

“I was driving my vehicle when the engine surged and then a transmission warning light came on and there was an immediate and complete loss of drive power. After the vehicle glided to a stop, there was no drive transmission in either forward or reverse. There was no pre-warning and no earlier incidence that led up to this issue. The vehicle is five years old with 39,834 miles and has had all routine maintenance and mileage interval services performed at the dealership, including its recent (Dec-25) 40,000-mile service. Thankfully this complete failure occurred when I was in my neighborhood and travelling 20mph; otherwise, the results could have been catastrophic had it occurred on a multilane highway at speeds of 65-70 MPH. The vehicle was towed to Audi of Indianapolis where the issue was identified as one broken bolt and two loose bolts for the transmission filter cap. This matches a known Audi Issue with a Technical Service Bulletin issued December 13, 2024, where they acknowledge a complete loss of power and a root cause of broken/loose bolts in the transmission filter. This is a known issue and is happening on low mileage well serviced vehicles. Because this…”

“Sunroof spontaneously shattered while driving. No other cars around when this occurred. Caused a very loud BANG. Was driving on the freeway when this occurred. Dealer would not confirm issue was spontaneous - felt something must have hit the car to cause this. No defined impact location on roof. Also, roof glass was pushed up in the middle instead of down like would be expected if something hit it from the outside. No warning before it occurred.”