After skipping the first practice session, Nasr and Ericsson drove out of the garage and onto the track during the second, timing 11th and 15th respectively.
Their participation comes despite a court order for the team to honour a contract with former reserve driver Giedo van der Garde and let him compete at the season-opener.
Sauber lost an appeal against the ruling and they are now facing a contempt of court action as van der Garde's lawyers claim they are blocking the Dutchman from taking part.
According to reports, van der Garde's lawyers want the Swiss outfit found guilty of contempt of court and its team principal, Monisha Kaltenborn, fined or jailed.
Friday's hearing was adjourned until Saturday morning, taking the legal imbroglio into a sixth day and raising the prospect it will not be resolved before Sunday's race.
But Justice Clyde Croft urged both parties to have "very sensible discussions" about a dispute which has overshadowed the start of the F1 season and thrown Sauber into turmoil.
Van der Garde claimed cash-strapped Sauber broke a deal that he would race for them this season when they instead opted for Nasr and Ericsson, who are heavily sponsored.
He originally won his complaint at a Swiss arbitration tribunal and on Wednesday Justice Croft backed the ruling, enforcing it in Australia.
Van der Garde's lawyer Jim Peters has said Sauber had made no effort to reinstate his client by helping him renew his "super licence" needed to race in Formula One.
The 29-year-old was a reserve driver for Sauber last year and competed for Caterham in 2013. He has expressed his desire to race for Sauber, which endured a poor season in 2014, failing to register a single point in 19 races.
They showed encouraging speed and reliability in pre-season testing, with Nasr going fastest on the second day of the first test in Jerez.
But Friday's run-out did not go well for Ericsson, who complained about his brakes and then had smoke gushing from a rear wheel, in a possible suspension failure.