What really caused McLaren's Chinese GP double DNS?

McLaren drivers Lando Norris and Oscar Piastri suffered two separate Mercedes HPP battery issues that prevented them from starting the Chinese Grand Prix.

A fortnight ago, the reigning world champions suffered a disastrous Sunday in Shanghai when Norris was unable to get to the starting grid, with the team scrambling to fix what was described as an electronics issue on the power unit side. Soon after, Piastri suffered a similar-looking issue while already on the grid, with the Australian's car having to be wheeled back as both drivers failed to start the grand prix.

After the race, team boss Andrea Stella said it was "quite exceptional" that McLaren suffered "two terminal problems pretty much at the same time on the same component, which in this case is on the electrical side of the power unit."

Following further investigation by McLaren's power unit provider Mercedes HPP, both Norris and Piastri were struck by battery issues of a different nature.

Autosport understands Norris' battery was plagued by a software problem that bricked the battery and made it unusable, and it is believed the unit is permanently damaged and removed from Norris' component pool.

Piastri was instead understood to be struck by a hardware issue with an auxiliary component connecting to the battery, and there is some optimism the Australian's battery can continue to be used after fixing the individual part.

Lando Norris, McLaren

Photo by: Sam Bagnall / Sutton Images via Getty Images

Norris' battery failure could have lingering side effects further down the road for the world champion if he suffers more battery-related reliability issues, having now lost one of his three batteries for the year. Drivers are usually allowed to use just two batteries, or energy stores per season, although they are allowed an additional example of each power unit component in 2026 to help ease teams into the all-new regulations.

"Of course, it hurt us as a team," Norris said on Thursday in Suzuka ahead of this weekend's Japanese Grand Prix. "It certainly didn't make us look good to have two cars not starting a race. I think what hurt more is the fact it was out of our control.

"But with HPP, we've worked hard to figure things out, to understand how it happened, why it happened. And of course, we'll do everything we can to make sure it doesn't happen again. But you live and you learn.

"It was a tough one for all of us. None of us want to have a weekend like that and especially start a Sunday like that. So yeah, it hurt a lot. But I think at the same time, a good time for us to learn and step back and move on to this weekend."