Toro Rosso suffered a mechanical problem in its debut race with Honda, the Australian Grand Prix, with Pierre Gasly retiring after just 13 laps due to an issue with the engine's MGU-H and turbocharger. Those components have been replaced on the Frenchman's car, as has the internal combustion engine (ICE), which was also damaged. As a precaution, the modified MGU-H and turbocharger have been fitted to the car of Brendon Hartley.

F1 controversially tweaked its engine regulations for 2018, limiting drivers to a maximum of three engines, MGU-Hs and turbochargers across 21 races, and just two MGU-Ks, energy stores and controlled electronic components. The change means Gasly and Hartley have already eaten into several of those component allocations with 20 races still to run. Drivers are given grid penalties for any additional units used throughout the year.

Honda's new F1 technical director, Toyoharu Tanabe, said: "Replacing components for the second race is obviously a difficult decision and not ideal, given that the number of Power Units and ancillary components is now limited to just three per season, however we believe this is the right way forward and we will continue our development in order to ensure the same issue does not reoccur. Although Sakhir is a tough track for the PU, we hope to move on from this difficult moment, as we focus on this race and those that follow."

Honda is embarking on a new era with Toro Rosso in 2018 after three disastrous years partnered with McLaren. That spell saw Honda struggle with both reliability and performance throughout, prompting McLaren to prematurely end what was supposed to be a 10-year partnership and switch to Renault power for the new season.