Audi WEC driver Loic Duval admits reliability is a concern for the German marque ahead of its return to testing.
While Audi and Toyota will continue their preparations in Europe, Porsche will be at Yas Marina to continue running in its updated Porsche 919 Hybrid.
For Audi, this week's testing programme ends a two-month break in testing after its week at Sebring in December.
Duval, who will share the No.8 Audi R18 e-tron quattro with Oliver Jarvis and Lucas di Grassi, said that having a trouble-free test will be the main worry.
"The car is really different and some great work has been done by the team. It looks really promising," Duval told Motorsport.com.
"The real question mark when you change everything like we have done is the reliability because it is all so new.
"The main thing is the hybrid which is brand new technology for us so even if we have worked with it for a while, it is still really complex," continued Duval.
"I think that in terms of performance we will be there, but of course it is still too early to say too much at this stage."
"There is still much to do"
Audi Motorsport boss Dr. Wolfgang Ullrich meanwhile admitted that the German manufacturer still has "much to do" with its testing programme before the new R18 is fully ready to race.
"We have a completely new car," Ullrich told Motorsport.com. "The goal of each new part is that it is better than the previous car.
"We're on schedule, we are in the process of understanding of systems, how to use them for performance and reliability. There is still much to do."
Asked to predict where Audi might be in this year's competitive pecking order, Ullrich added: "You never know until the first race. We are focused on our work, we know that we must make progress with the new car.
"It is certain that the competition will be at a very high level this year. Toyota year has a new car, we have a new car, both will be faster than last year, so the competition will be intense."
Additional reporting by Basile Davoine