In the hidden order of URu₂Si₂ the resistivity at very low temperature shows no T² behavior above the transition to superconductivity. However, when entering the antiferromagnetic phase, the Fermi liquid behavior is recovered. We discuss the change of the inelastic term when entering the AF phase with pressure considering the temperature dependence of the Grüneisen parameter at ambient pressure and the influence of superconductivity by an extrapolation of high field data.