Renault have insisted that they are not 'months' behind schedule but admit that they are behind rivals Mercedes and Ferrari.
Renault endured a troubled start to Formula 1's new era at the first test at Jerez as customers Red Bull, Toro Rosso and Caterham completed just 151 laps overall.
But head of track operations Remi Taffin insists that Renault is in a better shape ahead of next week's test in Bahrain.
"We're still behind schedule, but it's not a question of months," said Taffin.
"We are at least where we would have sought to be for the first test, so maybe now we are three weeks behind, and now we are on a recovery plan. We're now going to go into Bahrain with what we would have liked to have finished the first test with."
"As for our rivals, let's put it this way, they are probably four days ahead of us as they had a proper test in Jerez, and we didn't."
Taffin is confident that Renault's four customer teams will be able to undertake reliable running when the test begins next Wednesday.
"With regard to the hardware we are now confident the problem we had in the first test has been solved and we will be in a position to go out in Bahrain without all these issues."
"As for the software we've improved our level. We're still behind our initial schedule, but now beyond what we would have done in the first test. Again we should be okay in Bahrain to go out on the first day with a car that should be working.
"We are ready to do what we would have liked to have done in the first test, which is to properly test the power unit and give our customers a way to discover their cars. If the work we have done recently is okay, which we think it is, then we should see the difference in Bahrain, with cars out on track, which will mean we have solved the problem."