Explained: The FIA Software Bug That Caused F1 Chaos in Malaysia

The first wet-weather race of the 2026 Formula 1 season descended into disarray during formation laps behind the safety car at the Sepang International Circuit. Race leader Max Verstappen was the first driver to report a sudden loss of drive at extremely low speeds, followed rapidly by Lewis Hamilton grinding to a halt alongside several other competitors. The widespread technical failures prompted race control to halt proceedings with a red flag, leading to a 40-minute delay before racing could officially commence near Kuala Lumpur.

Software Glitch Traps Cars in Low-Speed Loop

Following the Grand Prix, FIA single-seater director Nikolas Tombazis confirmed to media outlets, including Motorsport.com, that the disruption was caused by an unforeseen bug in the standardized software developed collaboratively by the FIA and teams over several years.

We didn’t manage to test the software as extensively as we would have liked because there’s been very little wet running this year. There was a bit of a combination of circumstances which caused this bug to kick in, Tombazis explained during a post-race media briefing. Basically, on the formation lap, some cars went very slowly and almost came to a standstill. There was a bit of a concertina effect between cars and some cars almost stopped completely. That bug prevented then the power to be redeployed and for the cars to start again.

The root cause lies in technical regulations that reduce electrical power deployment down to 250kW during wet conditions. While teams including Red Bull and Racing Bulls had previously evaluated the wet-weather software, it had not undergone validation at the ultra-slow crawling paces typically dictated behind a safety car.

It was mainly in some sectors where the full power was reduced. I don’t know exactly what speed that was, but some cars reaching this very low speed somehow entered into a loop, which meant they couldn’t re-accelerate and then it looked as if they came to a stop.

The failure left drivers powerless in the cockpit as throttle inputs failed to engage the drive units. Haas driver Oliver Bearman expressed his shock at the incident: I’ve never seen or felt anything like that. I was shocked that… I didn’t even know that the FIA could control our throttle pedal. That was quite scary, actually, Bearman noted. My throttle pedal just stopped working. It was like it was not connected and the engine was just idling. It was so weird, I mean, shocking.

While the internal combustion engine is not designed to deactivate at such speeds, initial findings suggest the glitch redirected all driver throttle application toward recharging the MGU-K instead of delivering forward momentum. Tombazis also clarified that while Mercedes-powered machinery initially appeared less susceptible, the discrepancy was purely circumstantial: Not all cars reached the same low speeds on the formation lap. There was a bit of a concertina effect. I think Max slowed down quite a lot, being at the front, and then some cars braked harder as they were surprised and so on. That caused some cars to experience the problem and some others to not experience it.

Emergency Software Patch Deployed During Red Flag

To resume the event, technical delegates were forced to rapidly develop and distribute an interim patch to all teams on the grid to bypass the restrictive code.

Fortunately, our guys understood the issue very, very quickly. I think the update was done very competently. It was obviously a rush job. The priority was to get running as quickly as possible again, so I think the reaction time was quite fast, Tombazis stated. It wasn’t a perfect job and, clearly, we didn’t test the updates, but I think it was the way to handle such a case.

The emergency modification effectively overrode the 250kW power limit constraints across the specific minisectors where the crawl speeds had initiated the bug. In some of the sectors, some of these reductions of power were overridden, Tombazis confirmed. Clearly, we didn’t have five days to do the updates. We only had a few minutes, but fortunately, I think we managed to do it without compromising any safety, any racing or fairness.

Why This Matters

Modern Formula 1 power units rely on intricate electronic control systems managing hybrid energy deployment, and the governing body’s control systems act as a universal governor during specific track conditions. When rain triggers both a safety car and the specialized 250kW wet-weather power reduction, software must seamlessly manage transition points without conflicting with basic throttle operations. The Sepang incident revealed a blind spot in testing procedures where extreme low-speed concertina effects had never been simulated under wet-weather energy limits.

Addressing why the oversight emerged in round 16 of the championship, Tombazis acknowledged the gap in pre-season preparation: The software was tested. It just wasn’t tested in those specific conditions. What caught us out was the fact that cars went in that very, very low speed, which was not normally contemplated.

When asked if the governing body should have anticipated safety car crawl conditions in the rain, Tombazis admitted: Well, any bug is a product of a mistake. I mean, I don’t know of any software that doesn’t have bugs and updates. Your computer probably gets updated every three days and those are all bugs. Of course, anticipating these things is what one hopes to do, but sometimes some very combination of events isn’t properly anticipated and causes the problem. I think if we had had a bit more testing, we probably would have managed to catch it in time and not to have such a situation.

The FIA faces a thorough post-event debrief to establish a permanent software resolution rather than relying on track-sector overrides. As Tombazis concluded: We would all like it to be simpler, but the fact is when you have as much electrical energy, it does make it more complicated. I think you appreciate that the race has now finished about one hour ago and we haven’t done a full debrief of the situation to see how we can avoid such an issue. Every race, we have a long debrief afterwards where we identify criticalities. Obviously, that was a major criticality and we need to make sure we avoid it. But can I guarantee it will never happen again? This specific problem, yes. A problem, no. But we will do our best to avoid it, of course.

Frequently Asked Questions

Why did the F1 cars lose power during the formation lap?

Cars entered a software-induced loop caused by traveling at exceptionally low speeds behind the safety car. In wet conditions, power is electronically capped at 250kW; when cars bunched up and crawled through certain minisectors, the FIA software erroneously directed throttle pedal inputs into recharging the MGU-K rather than propelling the car forward, leaving the engine merely idling.

How did the FIA resolve the issue to restart the race?

During a 40-minute red flag period, the FIA created and distributed an emergency software update to all teams. This patch manually overrode the 250kW wet-weather power reduction limits in the specific minisectors where the crawl speeds had triggered the failure, enabling the field to accelerate normally.

Were certain engine manufacturers favored or protected from the glitch?

No. While Mercedes-powered cars appeared less hindered at first glance, FIA single-seater director Nikolas Tombazis confirmed the discrepancy was entirely dependent on track position and speed. Only the vehicles that experienced severe concertina braking and dropped below a critical speed threshold triggered the system glitch.