Heavy rain delayed the start of the Bahrain Grand Prix at Sepang by 40 minutes on Sunday, before a software bug caused engines to stall during a chaotic formation lap, halting multiple Formula 1 cars on the grid.
The Sepang circuit turned into a testing ground for unexpected electrical vulnerabilities on Sunday. Following a torrential downpour that pushed the race start back by 40 minutes, the ensuing formation lap triggered widespread technical failures across the field as drivers navigated the soaked track.
The damp conditions proved immediately punishing for front-row starters and midfield contenders alike. Isack Hadjar spun his Red Bull before managing to recover it, while drivers behind him encountered much more stubborn mechanical resistance as engines lost throttle response.
Engine Software Failures Freeze Grid Cars
Max Verstappen experienced a sharp, sudden deceleration during the formation lap due to an apparent motor software glitch. That same electronic fault quickly crippled Lewis Hamilton’s Ferrari, leaving the car completely motionless on the straight alongside several other stalled machines.
The heavy spray and slow speeds affected multiple teams simultaneously. Gabriel Bortoleto, Nico Hülkenberg, Esteban Ocon, and Arvid Lindblad suffered the identical power unit malfunction under the wet conditions, while Lando Norris briefly lost control of his McLaren in the slippery conditions. The resulting cluster of immobile vehicles across the track forced race officials to display the red flag and order all 22 cars back to the pit lane while crews assessed the grid.
FIA Explains Power Unit Bug and Testing Shortfalls
Nikolas Tombazis, responsible for single-seaters at the FIA, pointed to a lack of competitive wet-weather running earlier in the year as the primary root cause. Because teams had completed very few competitive laps in genuine rain during the season, developers failed to anticipate how the power units would react to cars moving at exceptionally slow speeds during the formation tour.
Tombazis elaborated on the specific on-track dynamics that triggered the software defect. Cars crawling near a standstill created a accordion effect through the field, bringing some vehicles to an absolute halt and awakening the dormant bug that blocked power deployment and engine restarts.
In fact, some cars were driving very slowly during the formation lap, coming almost to a standstill. There was a bit of an accordion effect between cars, and some cars stopped almost completely. And that bug prevented the power from being redeployed and the cars from restarting. I think that if we had tested a bit more, we probably could have discovered it in time and prevented such a situation. Nikolas
Driver Frustration and Emergency Software Patch
The grid delay drew sharp criticism from competitors managing the new-generation machinery, which relies on 47 percent electrical power under current regulations.
Norris argued that the electronic complexity introduced unnecessary vulnerability.
Sergio Perez similarly characterized the grid malfunction as an unacceptable failure.
To resolve the grid stoppage, governing body personnel raced against the clock to build, distribute, and install an emergency software patch across the affected teams before racing could resume.
The emergency fix extended the total wait time by 53 minutes before cars headed back out.
So all of that took about 20 minutes. It may have felt like five hours to spectators waiting for a race and to everyone else, which is understandable, and we apologize for that. But I think that, given the problem, it was a fairly quick response. Nikolas
Not every participant shared the frustration over the lengthy interruption. Fernando Alonso, who finished eighth for Aston Martin-Honda at the conclusion of an unusually good day, offered a lighter perspective on the delays compared to his usual weekend hurdles.
Fernando Alonso noted, I had 50% DNFs this year, they never stopped the race for us.