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Sepang, The Rain, and F1’s Sensors Exposed and Software Weakness
The 2026 Bahrain Grand Prix in Malaysia was barely underway when Formula 1 found itself facing a problem that had nothing to do with tyres, engines or a conventional mechanical failure.
Instead, the rain exposed a weakness buried inside the new-generation Formula 1 power-management system.
A heavy tropical downpour delayed the scheduled start at Sepang by 40 minutes. When the field finally headed out for the formation lap, the circuit was still wet and extremely slippery. But then something far stranger happened: cars began slowing dramatically, with several drivers reporting that their throttle inputs were no longer producing the expected power.
Pole-sitter Max Verstappen was among the first to experience the problem. Lewis Hamilton, starting alongside him for Ferrari, encountered the same issue.
Hamilton reported to Ferrari that he was pressing the throttle but getting nothing from the car. He eventually crawled around the circuit before the situation escalated and the start procedure was suspended.
What initially looked like a collection of power-unit failures turned out to have a much more unusual explanation.
The rain was the trigger — not the sensor
The FIA has now confirmed that there was no indication that track sensors were damaged or malfunctioning because of the rain.
Instead, an unusual combination of circumstances caught the 2026 cars’ software off guard.
According to FIA single-seater director Nikolas Tombazis, the formation lap created an unprecedented combination of very low engine speeds, low-grip conditions, wet-weather energy-management settings and Sepang’s sector configuration.
That combination resulted in an unintended loss of power on several cars.
In other words, the rain didn’t simply make a sensor malfunction.
It created conditions that the software had not been properly tested to handle.
That distinction is important.
Why did the cars stop?
The 2026 regulations have placed considerably greater emphasis on electrical power and energy recovery. The cars therefore rely heavily on software to determine how electrical energy is managed and redeployed.
At Sepang, the field was travelling unusually slowly because of the wet track. Cars bunched together in what Tombazis described as a “concertina effect,” with some almost coming to a complete stop.
That combination triggered a software bug that prevented power from being redeployed properly.
The result was bizarre: drivers could press the accelerator, but the car would not respond as expected.
It explains why the problem initially appeared to be much more serious than it actually was.
Several cars were affected, including Hamilton’s Ferrari, Verstappen’s Red Bull and cars from other teams. The FIA ultimately suspended the start and gave teams time to correct the problem.
The FIA had to patch the cars before racing could begin
This is perhaps the most extraordinary part of the incident.
The solution wasn’t replacing a component or repairing a damaged sensor.
The FIA issued an updated software release.
The technical department removed the energy-limit constraint in the affected sectors, and teams then installed the update onto their power-unit systems during the delay.
The whole process contributed to another lengthy delay before the race finally got underway.
Once the software update was applied, the cars were able to complete the race without the same formation-lap problem returning.
Why wasn’t this discovered before Sepang?
This is where the FIA has effectively admitted there was a testing gap.
The 2026 cars had experienced very little competitive wet-weather running. Although wet conditions had been encountered during tyre testing and pre-season running, the specific combination experienced at Sepang had not been properly replicated.
Tombazis acknowledged that the software had not been tested extensively enough in those circumstances because there had been so little wet running during the season.
The FIA has now confirmed that it will conduct a full review with the teams and power-unit manufacturers.
A warning for the new era
Sepang therefore becomes more than just another chaotic wet race.
It was effectively a real-world stress test of Formula 1’s new electrical architecture.
The 2026 regulations were designed around a much larger electrical contribution to the power unit, making software and energy management increasingly important to performance. But Sepang demonstrated that the complexity also introduces a different kind of vulnerability.
The cars didn’t suffer a traditional mechanical failure.
They encountered a situation where the software’s interpretation of the conditions prevented the power from being delivered as the driver expected.
And that makes the incident particularly significant for Ferrari.
Hamilton was sitting second on the grid, immediately behind Verstappen, when his Ferrari became one of the cars affected. Yet after the software issue was resolved, Hamilton went on to recover spectacularly and finish third, with Charles Leclerc taking fourth. Verstappen won ahead of Mercedes’ Kimi Antonelli.
The rain created the chaos.
But it was the 2026 software architecture that turned that chaos into an F1-wide technical problem.
And after Sepang, the question isn’t whether the cars can cope with rain.
It’s whether Formula 1 has now discovered a new vulnerability in the increasingly software-dependent machinery of the 2026 era.
