Minardi entered 2003 with significant uncertainty. Engine supplier Asiatech had ceased operations, leaving the team to negotiate urgently for a replacement. A deal with Ferrari fell through due to the prohibitive lease fee of £15 million; Cosworth was ultimately secured, but the late agreement forced designers to rework the PS03's engine bay, which had originally been designed around the Asiatech unit.
Tyre supply was equally turbulent. Michelin withdrew as supplier in November 2002, leaving the team without rubber when Jos Verstappen arrived to test in Valencia. Verstappen ended up testing the 2001-specification PS01 on Avon Formula 3000 tyres as a workaround. An agreement with Bridgestone was not finalised until late February 2003, just 24 hours before the cars were packed for transport to Australia.
The PS03 was also the last Formula One car to adopt the power-assisted rack-and-pinion steering system, as it became mandatory from the 2003 season onwards.
Jos Verstappen returned to Formula One after sitting out the 2002 season. Justin Wilson joined the team in notable circumstances: his father and former F1 driver Jonathan Palmer organised a crowdfunding effort after Wilson missed out on a Jordan drive due to his height. Minardi agreed to build a cockpit sized to fit him. Both drivers were reported to have paid £2 million for their seats. Matteo Bobbi served as test and development driver for a third consecutive season.
In July, Wilson was signed by Jaguar Racing as a mid-season replacement for Antonio Pizzonia, and Nicolas Kiesa took his seat at Minardi for the remaining five rounds.
The 2003 campaign was deeply difficult. The PS03 failed to score any championship points across the entire season and retired from eleven races. Wilson retired from the opening four Grands Prix consecutively. At the Malaysian Grand Prix, he suffered from exhaustion and temporary neck paralysis caused by his HANS device coming loose, restricting arm movement inside the cockpit.
Verstappen came close to points at the rain-soaked Brazilian Grand Prix, a chaotic race that eliminated numerous front-runners including Michael Schumacher, but retired on lap 31 after spinning off. Kiesa, who completed all five of his starts, finished each race but remained well outside the points.
Minardi finished last in the Constructors' Championship with no points.
The team started the year heavily sponsored by Stoddart's European Aviation brand against a mostly black backdrop. New deals were struck with energy company Gazprom and investment firm Superfund. Gazprom defaulted on payments and was removed from the car before the Austrian Grand Prix, at which point Dutch company Trust increased its involvement and the livery shifted to a black-and-white split scheme.
A Malaysian flag was displayed at the Malaysian Grand Prix alongside the message "Malaysia for Peace." A deal with tools brand Stayer later in the season also went sour when payments failed to arrive; at the Japanese Grand Prix, the team covered the Stayer logo with red text reading "Not paid" and raced the cars in that modified state.
Revenue distribution talks between team principals and the FIA ran through the season, with Ron Dennis and Frank Williams notably resistant to proposals that would have supported Minardi financially. FIA president Max Mosley criticised their position publicly. Bernie Ecclestone purchased a minority stake in the team partway through the year.
The PS03 season encapsulates the hand-to-mouth existence Minardi endured through the Stoddart era: chronically underfunded, perpetually scrambling for engines and tyres, yet continuing to field cars and develop drivers. Justin Wilson would go on to a successful IndyCar career before his death in a 2015 racing accident. Verstappen remained active in motorsport for many years, with his son Max Verstappen becoming a multiple Formula One World Champion. The PS03 represents one of the last seasons before Minardi's identity was extinguished, as the team was sold to Red Bull ahead of 2006 and reborn as Scuderia Toro Rosso.