Audi’s upcoming A5 Avant has suffered a setback as a prototype broke down on the Nürburgring.

Details are limited, but our spy photographer tells us that the wagon was tackling the green hell when an unknown issue arose. It’s not entirely clear what transpired, but something occurred shortly before the Caracciola-Carousel section of the Nordschleife and forced the car to pull over to the side of the track.

The issue appears to have been serious enough that a tow truck was dispatched to bring the car back to Audi’s development center. Regardless of what caused the breakdown, accidents happen and it’s better for them to occur in the prototype stage than when the vehicle is in production.

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Putting the mishap aside, there isn’t much we haven’t already seen. However, it’s a spy photo double feature as the S5 Avant also came out to play. As a result, we can easily compare the two models and see there aren’t many differences besides a four tailpipe exhaust system.

While the exterior design is evolutionary, the cabin will get a high-tech makeover that features two freestanding displays including a sizable infotainment system. They’ll be joined by a minimalist shifter and a new steering wheel.

Despite sporting a new name, the wagon will be fairly evolutionary as it’s slated to ride on the MLB Evo platform and feature turbocharged 2.0-liter four-cylinder engines. The latter are expected to embrace electrification and feature mild-hybrid technology. The S5 Avant will also be electrified, although it doesn’t appear to be a plug-in hybrid as we can’t see evidence of a charging port.

Pictures: Baldauf for CarScoops