Sebastian Vettel's bid for a record-equalling fifth straight Formula One world title could not have started in more disappointing fashion.

For reigning champions Red Bull, Vettel, and engine partners Renault, the second day of pre-season testing proved to be another to forget.

Just 31 hours after taking the wraps off the RB10 in the pitlane at Jerez, Vettel was departing the circuit a frustrated figure.

That followed two days spent predominantly twiddling his thumbs, as he completed a grim total of 11 laps.

On the opening day on Tuesday, Vettel had to wait until 15 minutes before the end of the session before finally taking to the track, managing three laps.

On Wednesday, the 26-year-old's day was done by 2pm local time due to an issue with the new energy store, with the German then leaving the track just before 4pm after a debrief, without even conducting his scheduled media duties.

The only remarks from Vettel came via Red Bull's press release as he said: "Obviously, we've not had a lot of running and a few problems to sort.

"With such big rule changes it's usual to have teething problems, and that's what tests are for, to sort those issues out.

"The next two days (with new team-mate Daniel Ricciardo at the helm) will be important to get some track time to prepare for the tests in Bahrain."

At the same time Vettel was departing, another Renault-powered car in the Caterham - driven by rookie Marcus Ericsson - was returning to the garage on the back of a flat-bed truck after stopping on track and with just 11 laps under its belt.

With Toro Rosso failing to run at all on Wednesday due to electrical issues, it means Renault's engines have completed a miserable 38 laps over the two days.

After four years of dominance in powering Red Bull and Vettel to title glory, Renault's head of track operations Remi Taffin acknowledged his company "are facing problems".

The switch to the new 1.6-litre turbo-charged powertrains, complete with the ERS (energy recovery system) is posing Renault significant headaches.

Despite that, Taffin said: "There are many problems we can see when we've got new cars, and also on our side, new power units.

"That could be different from one team to another, but for sure we know on our side we had one problem we clearly identified and we wanted to fix it.

"We could not fix it for this morning so we decided to do as much as we could to make sure for tomorrow, and especially for Red Bull and Toro Rosso, we are sure we can take to the track at nine o'clock.

"We are confident that tomorrow morning we will have all three cars on track. We are going to fix the hardware."

After failing to turn a wheel in anger on Tuesday due to McLaren's own problems, Jenson Button topped the timesheets after day two.

Completing 43 laps, the 34-year-old Briton's best was a one minute 24.165secs, just over half a second ahead of Kimi Raikkonen in his Ferrari.

After a day of frustration on Tuesday, Button was happy enough as he said: "It's always a weird one sat in your motorhome all day long hoping they'll build the car.

"We had a lot of issues yesterday and it's nice to see we were able to solve them overnight. It wasn't a lot of laps today, but it's been a positive start.

"There's no horrible issues with the car itself, no big issues with the power unit in terms of how it delivers, so the basic car itself is where we want it to be.

"We always aim to have a good base because the way that it's going to improve throughout the year, and how we're going to add to this car, aerodynamically, and also development in terms of the engine, is massive.

"So having a good base is important, so I'm happy."

Mercedes-powered cars clocked up the miles as Williams' Valtteri Bottas managed 35 laps and Sergio Perez 37 in a Force India that suffered its own technical issue midway through the afternoon.

Way out in front, however, was Nico Rosberg in the works car as he rattled off 97 laps, more than the entire field completed on Tuesday.

That was after a late start as the team put the finishing touches to the W05 following a front-wing failure on Tuesday which sent Lewis Hamilton into a barrier.

A delighted Rosberg said: "That was a great team effort today, we were able to do a lot of mileage which is great for our learning process."

Sauber's Esteban Gutierrez was sixth on the timesheet, completing 53 laps to give Ferrari-powered cars a total of 100 for the day.