An intriguing question in superconductivity is how to efficiently detect signature of the collective excitations associated to the superconducting order parameter. The feature associated to collective mode can indeed provide insight on the pairing symmetry of the order parameter and to other features of the superconducting state. We address this question by we theoretically model a 2D THz pump-probe spectroscopy experiment for a two-band superconductor. Two-dimensional spectroscopy has proven to be an important method with wide applications ranging from rovibronic excitations in bio-molecular systems, excitons in semiconductors, to magnons in antiferromagnets and has been recently applied to superconducting collective modes. To numerically compute the non linear dyanamics we adopt a pseudospin model and we chose realistic parameter to model the pulses and as well for the superconducting state, reflective of MgB2. The numerically evaluated 2d spectrum shows, in addition to the first and third harmonic signals, the presence of sidebands along ω= ωΔt ± Ω, where Ω is associated to the Leggett mode frequency of the system. We proceed by analytically deriving an expression for the non linear current. Our results show that the extension of 2d techniques to the superconducting realm may therefore provide an important new avenue to investigate the physics of superconductors.