Lotus missed the first test at Jerez last month, but made its public debut at Sakhir on Wednesday - although Grosjean was only able to do eight laps.
He said that while he was unsure of the exact nature of the problems that kept Lotus in the garage, he was not expecting anything else.
"To be honest, there are so many things going on at the rear of the car that I can't understand everything, but it was related to the engine or batteries or things like that. Nothing too crazy," said Grosjean.
"Hopefully we can understand it and get better solutions for tomorrow and the day after.
Lotus E22 in detail in the Bahrain test gallery
"I don't really care about set-up work, that's going to be when we are in free practice. It's just about fixing all the issues and making sure the car is in one piece when we do long runs.
"It is what it is. We have a car, and we know that with all these changes it could have some issues.
"On the other hand, if the car is born well then we will have three sessions in practice in Melbourne to put it on the right foot and then start from there."
Bahrain test day one report
Lotus's engine supplier Renault has had a troubled start to the 2014 F1 season.
While Caterham's Renault-powered CT05 managed 68 laps on Wednesday, Red Bull, Toro Rosso and Lotus covered just 27 between them.
Grosjean added that he did not get any unpleasant surprises from the car in the laps he did manage.
"On the few laps I did, although it was miles from the pace, the car felt alright," he said.
"There are still things I want to tune but nothing unexpected or very strange."
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