Audi’s inaugural Formula 1 power unit was identified as the principal cause of a cascade of reliability and operational failures at the Miami Grand Prix, newly installed Audi Racing Director Allan McNish said. The team described the weekend as “disastrous” after a series of mechanical faults left both cars unable to make meaningful progress and forced reactive measures that prevented normal development and running.

The failures on the Miami weekend included a pre-start fire that stopped Nico Hülkenberg from taking the Sprint start and, later, an overheating drivetrain that forced his retirement while en route to the grid. Gabriel Bortoleto was disqualified from the Sprint for exceeding the maximum engine intake air pressure, and still finished 12th in the Grand Prix. The team also reported a brake fire, an additional unspecified fire and a forced gearbox change during the event. McNish said Audi must “tidy up” a series of reliability and operational problems and called the intake-pressure breach “not performance-beneficial but an operational error the team must eliminate.”

Audi attributed the incidents in part to learning to deploy its new power unit, saying those reliability problems have limited competitive progress and prevented normal weekend running. McNish acknowledged other power-unit manufacturers have experienced difficulties with new-generation systems this year, and said Audi’s immediate priority is to diagnose root causes, restore basic reliability and ensure both cars can reach race starts after pre-race retirements earlier in Australia and China and the setbacks in Miami.