For 1977, the car was entered by Schmidt's ATS Wheels business and run under the name of ATS Racing Team. The ATS-Penske PC4, now painted yellow, debuted in the 1977 United States Grand Prix West with Jean-Pierre Jarier at the wheel, where the Frenchman scored the team's single point of the season. A second PC4 was eventually entered for Hans Heyer (who started the 1977 German Grand Prix despite failing to qualify) and Hans Binder (3 races) but the team's fortunes sank and Schmidt quit after the Italian GP, before returning in 1978 with his own chassis. A third PC4 was built by Penske for Interscope Racing, who entered the car in the United States and Canadian Grands Prix, driven by American Danny Ongais with no results.