Pierre Gasly and Brendon Hartley will both race with new engines in Bahrain after the problems experienced in round 1.
Each driver is only allocated three engines for the duration of the 2018 season before penalties are applied.
Honda’s technical director explained the difficulties experienced with the engine.
“Given the problems we encountered in Melbourne, we have decided - to change the MGU-H and turbocharger,” said Toyoharu Tanabe
“The MGU-H and turbo have both been modified, in light of what we learned in the first race.”
Toro Rosso had initially impressed fans with their positive running in testing only to be let down in Melbourne.
With two engines now having to run 20 races, it’s almost inevitable that Toro Rosso will require penalties at some stage.
Red Bull won’t be impressed with the performance of the engine so far as they look at the possibility of using a Honda engine in 2019.