The CO₂ NLTE problem has been extended to account for all vibrational states and transitions included in the HITRAN-92 database of spectroscopic parameters. The set of the rate constants for V-T and V-V collisional processes and the model for pumping the CO₂ states by OH(ν) have been revised. The effect of the vertical kinetic temperature and O mixing ratio profiles on the vibrational temperatures of the ν₃ mode manifold states as well as the dependence of these temperatures on the solar zenith angle have been examined in detail. In the daytime, the lower boundary of the NLTE layer tends to reach the ground when the energy of the ν₃ mode manifold states increases.