Crossed-beam scattering experiments were carried out at collision energies of 4.51 and 2.71 eV to elucidate the electronic states involved in the nondissociative and dissociative electron-transfer reactions observed following CO22+/CO2 collisions. Specifically, we focus on the observation that, in the dissociative electron-transfer reaction, forming CO+, the majority of the CO+ product ions are formed via electron capture by the CO22+ rather than via ejection of an electron from the neutral CO2 reaction partner. The main channels resulting in nondissociative electron transfer are reactions of the ground (X-3 Sigma(-)(g)) and excited states of CO22+ to give different combinations of the ground and excited states of the product pair of CO2+ ions in which the combination AA appears to be significant. The CO+ ions appear mainly to arise from slow dissociation of CO2+(b(4)Pi(u)) formed following electron capture by the ground state of the dication reactant (X-3 Sigma(-)(g)), with possible contributions from electron capture by higher triplet excited states of the dication.