Irradiation with 1.4 GeV 208Pb ions was used to induce artificial disorder in single crystals of iron-arsenide superconductor Ba(Fe1−xCox)2As2 and to study its effects on the temperature-dependent London penetration depth and transport properties. A study was undertaken on overdoped single crystals with x=0.108 and x=0.127 characterized by notable modulation of the superconducting gap. Irradiation corresponding to the matching fields of Bϕ=6 T and 6.5 T with doses 2.22×1011 d/cm2 and 2.4×1011 d/cm2, respectively, suppresses the superconducting Tc by approximately 0.3 to 1 K. The variation of the low-temperature penetration depth in both pristine and irradiated samples is well described by the power law Δλ(T)=ATn. Irradiation increases the magnitude of the prefactor A and decreases the exponent n, similar to the effect of irradiation in optimally-doped samples. This finding supports universal s± pairing in Ba(Fe1−xCox)2As2 compounds for the entire Co doping range.