F1 Software Bug Nearly Stopped Cars on Track, Forcing Delayed Grand Prix Start

A software malfunction left several Formula 1 cars with little or no throttle response during the formation laps of the Bahrain Grand Prix in Malaysia, forcing race control to abort the start and delay the race by more than 40 minutes.

The FIA said the problem was caused by a bug in electronic control software it supplies to teams. When the cars slowed to a crawl behind the Safety Car in heavy rain, a software bug prevented electrical power from being redeployed.

One early explanation suggested that throttle input was diverted towards recharging the electric motor, leaving drivers with almost no response from the pedal.

The fault appeared after the field slowed dramatically behind the Safety Car in heavy rain at Sepang International Circuit. FIA engineers produced an emergency software patch during the delay, which teams installed on the grid before the race could restart.

Software Bug Left Cars Unable to Accelerate

In wet weather, the 2026 rules reduce how much electric power the cars can use. At some parts of the Sepang track, that electric power can be cut off completely. Heavy rain then forced the cars to slow almost to a crawl behind the Safety Car. Verstappen slowed first, causing the cars behind him to brake suddenly, with some nearly stopping.

As the cars slowed, engine power and electric assistance dropped. That may have triggered a software setting called 'continuous offset' on some cars. The 60-second setting was designed to stop teams from switching off the MGU-K on purpose.

One initial explanation suggested the software instead sent the drivers' throttle commands towards recharging the electric motor, leaving the engines idling and the accelerator pedals barely responding.

FIA Said Wet-Weather Conditions Exposed the Bug

Nikolas Tombazis, the FIA's single-seater director, said the software had been tested with teams but that previous wet-weather running did not reproduce the conditions seen at Sepang. Testing had not covered cars moving at extremely low speed in a tightly packed field behind a Safety Car.

The combination of low engine speeds, wet-weather energy restrictions, limited grip and the circuit's sector layout exposed a problem that had not previously been detected.

Drivers who maintained slightly higher speeds were able to avoid the issue. Ferrari-powered cars appeared to be more affected, but the FIA said the problem was not caused by a fault specific to Ferrari.

FIA engineers found the software problem and created a patch in about 20 minutes. The fix removed the 250kW limit in the parts of the track where the problem was happening, allowing the affected cars to race.

Tombazis said there was not enough time to put the emergency fix through the usual testing process, which normally takes several days. Instead, the patch worked around the problem by removing the wet-weather power limits in those areas.

The FIA, teams and power unit makers are now investigating what went wrong and are expected to develop a permanent fix.

Drivers Questioned F1's Growing Complexity

Lewis Hamilton said he had to stop his car and carry out a full reset, something he said he had never previously needed to do in his career.

Hamilton and Verstappen compared the chaotic formation laps to a 'Lego race'. Verstappen said cars were running five-wide down the straight while drivers were unsure what was happening.

Oliver Bearman said his throttle felt disconnected from the engine and called the experience 'quite scary'. Sergio Pérez described the incident as 'totally unacceptable for the sport'.