Seven failed satellite calls were received on Saturday, Argentina's defence ministry said, raising hopes that the 44 crew members on board ARA San Juan were trying to re-establish contact.
"We analyzed these signals, which as we know were intermittent and weak", said Gabriel Galeazzi, a naval commander.
"With the collaboration of a US company specializing in satellite communication, we are now working to determine the precise location of the transmitter of the signals, given the presumption that it could be the submarine carrying 44 crew members on board", the statement said.
Argentina is working on tracing the location with an unnamed US company specializing in satellite communications, the ministry said.
High winds and heavy seas in the South Atlantic are affecting the ability of assets to conduct operations but the UK remains committed to efforts to find the missing submarine as soon as possible.
In response, a U.S. Navy P-8A Poseidon plane is expected to arrive in the country Saturday evening, a British ice patrol ship stationed in the Falkland Islands is expected to join the search Saturday, and a Chilean aircraft has been dispatched.
Claudio Rodriguez, whose brother Hernan is aboard the submarine, was hopeful, saying the satellite signals suggested the vessel was still afloat and would be found.
The crew's relatives have gathered at the Mar del Plata Naval Base in anticipation of hearing news about their loved ones.
News of the stricken submarine had even reached the Vatican.
Missing Argentine Navy sub may have sent distress signals, US Navy sends help
Argentinian president Mauricio Macri tweeted that the country would use 'all resources national and international that are necessary' to locate the vessel.
The U.S. Navy ordered its Undersea Rescue Command based in San Diego, California to deploy to Argentina to support the search for the submarine.
The PRM can submerge up to 2,000 feet for docking and can rescue up to 16 people at a time.
That maintenance included the replacement of its four diesel engines and its electric propeller engines, according to specialist publication Jane's Sentinel. Contact wasn't made and nothing was transmitted, but the signals, if from the sub, are the first signs of life from the ARA San Juan.
The 213-foot long submarine was built in 1983 by Germany's Thyssen Nordseewerke.
The vessel disappeared 430km (267 miles) off the Argentine coast.
He said: ' Detection has been difficult despite the quantity of boats and aircraft'.
It is thought that the submarine may have had communication difficulties caused by a power cut.