Pierre Gasly and Brendon Hartley have said that an error in communication resulted in the pair colliding at the end of the back straight in China.
Gasly was given a 10-second penalty for being at fault for the collision which prompted the Safety Car to set up a grandstand finish at the Shanghai International Circuit.
And it capped off a miserable weekend for Toro Rosso after the highs of Bahrain, with Gasly finishing way down in P18 and Hartley forced to retire late with a gearbox problem.
"They told me on the radio 'okay, Brendon is going to let you pass, at the end of the straight'. So I expected him to let me by, I went on the inside," Gasly told reporters in China.
"I expected him to leave me a bit of space to turn, and finally when he started to turn like normally and I was on the inside, was too late and there was nothing I could do.
"I tried to brake and avoid him, was way too late, we made contact and basically that was it.
"It was a shame, because of course the last thing you want is to have contact with your teammate, just a shame, but I think we misunderstood each other.
"I expected him to do something and he probably expected something else."
Hartley said that Gasly was under the wrong impression and that he was not leaving room for him to overtake.
"It was clearly a bit of miscommunication," Hartley said.
"We switched positions on the first stint as well because I was struggling on the ultrasofts, I let him by on the exit of Turn 14 and the second time I was asked, I planned to do the same.
"But my feeling is he must have thought that I was opening the door on the entry, which was not the case."