Known sestertii of Pupienus as MAXIMVS apart from the PAX PVBLICA type:
P M TR P COS II P P, Genius of the Senate (often misinterpreted as "Emperor") standing left, BMC 97*, citing Hess 211, 1932, Walters/Webb, lot 1334.
VICTORIA AVGG, Victory standing left, BMC 98*, citing Cohen 40 (Paris). Illustrated specimens: Peus 200, 2010, lot 523; Cederlind 164, 2012, lot 256.
The PROVIDENTIA DEORVM type is not attested with MAXIMVS. Could you obtain an image of the coin and post it here, ideally with weight and die axis too?