The 26-year-old managed only 14 laps on Wednesday but is confident that the troubles that afflicted Red Bull in Spain have been solved.
"We have fixed the problems from [Jerez], we had a problem with temperature which we seemed to have fixed today with the couple of laps that we could do," said Vettel, who was halted by a spin caused by a rear brake problem, which is believed to be overheating-related.
"Very often, you fix one problem then another problem pops up so I think there is stuff to do on the Red Bull Racing side in terms of reliability, temperatures, in general around the car, and there's stuff on the Renault side.
"It's not fair to separate those two, we are a team and we have been very successful together.
Bahrain test day one report
"It's not the start we were hoping for but we still have some time and clever people on board, who can hopefully fix the problems."
Vettel, who completed only 11 laps in the RB10 at Jerez, did have the chance to get an impression of the car's performance for the first time.
While he needs more running to draw any definitive conclusions, he is confident the problems will be solved and that he will soon be able to get the time in the car he needs.
F1 testing in pictures
"It's fairly difficult to judge where we are, I haven't had much of a car yet," he said.
"The first gut feel is OK but we need running to judge the car, to judge reliability, to judge performance.
"It's difficult to get a feel when you have only done a couple of laps and not everything is running smoothly.
"We didn't expect to have that many problems right at the beginning, but it is what it is and I know that everyone is 100 per cent working flat-out trying to find solutions as quick as we can."
AUTOSPORT Live coverage of the Bahrain F1 test resumes at 6am UK time on Thursday.