Mercedes and McLaren both had their running truncated by gearbox problems on the second day of testing in Bahrain.
Mercedes's Lewis Hamilton spun into the gravel during the morning session but quickly returned to the circuit and amassed 89 laps before Mercedes has to curtail their running.
"There are no specific problem areas, just lots of different things we need to improve," said Hamilton.
"It's important to get as much mileage under our belts as we can and just as important to discover any problems before we get to Melbourne. It might be frustrating at times but finding them at this stage is actually a positive. We really don't know where anyone stands right now and we have enough to concentrate on without looking at how other teams are getting on."
"The focus is on ourselves and will continue to be right up to the first race. Today was a fairly average day but I've got one more to go before we get to Melbourne, so hopefully that will be a bit more productive."
Jenson Button spent most of the day in the garage but still racked up 52 laps in the MP4-29.
"We had a problem within the gearbox – it took a while to change, as anything within the power-unit does these days – but we got back out at the end, and everything ran smoothly, which was good," he said.
"It was a shame to lose that time – it’s the first major issue we’ve had this winter; but it’s better to suffer it here, rather than at a race weekend.
"We were still able to do a long-run on high-fuel this afternoon. The basic car is good, and there’s a great deal of potential there, but there’s still a lot of work to do. We have a good understanding of the power-unit, and we know how to race it, but, in terms of balance and grip, the car isn’t quite there yet.
"But I know we’ve got some good improvements in the pipeline – and they should help us close the gap to the front of the grid."