The generator matrix

 1  0  0  0  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  2  1  1  1 2a  1  1  2  1 2a  1  1  1  1  1  1  1 2a  1  2  1 2a  1  1  1  1  1  1  1  0  1  1  2 2a+2  1  1  1  1  1  1 2a  1  1  0  0 2a+2  1  1  1 2a  1 2a+2  1  1  1  1  1  0  1  1  1  1  1  1  1  1  1  1  1  1
 0  1  0  0 2a+2 2a 2a+2  2  2  2  1 3a+2 3a+3 2a+3  1 3a+1 2a+3 a+2  a  1  2 2a+2 2a  1 a+3 3a+2  1 3a  1  a a+3  3  3  3 3a+3  1  1  a  1 3a  2 2a 3a+1 a+3  2 a+2  3  a  1 3a a+1 2a  1 2a+1 3a+1 3a a+2 a+1 a+2  1 2a+2 a+3 2a  1  1 2a+1 a+2 2a+1  1 a+3  0 3a+3 3a+1 a+2  3  1  1  1 3a+2 3a+1 a+1 a+1 2a 3a+3 2a+1  3 2a+1 a+3 3a
 0  0  1  0  0  2  2 2a+3  a a+1 2a  2 2a+2 2a+2  0 3a+3 2a+1 3a  1 3a a+2  1 2a+3  3 3a  a  3 a+3 3a+2  a 2a+3 3a+3  1 2a+2  2 a+2  0  3 2a  1  1 a+1 3a+2 3a+1 3a+3 a+2  3 2a a+3 a+1  1  1 2a+2 3a a+2 2a+1  0  2 3a+3 2a+1 2a+1 a+1  1 a+3 3a 2a 2a+3  1 3a+3 3a+3  1 3a+3 3a+1 a+3 3a 3a+1 2a  a 2a+2  3 2a+2 3a+1 2a+1 2a+2 a+1 2a+2  1 3a a+3
 0  0  0  1  1 3a+2 a+1 a+1 3a+3 a+3 3a+1 3a+1 3a+1 3a+2  3 3a  3  2 2a 3a+2  0 2a+1  a 3a a+3 a+1 2a+2 3a  3 2a+3  2 2a+3 a+3 2a+2  0 a+2 3a+2  3 2a+3 3a+2  3 2a+3  2  1 a+2  a 3a+2 3a  2 2a+1  a 3a+1 a+1 a+1 2a+3 a+3  2  1 2a+2 3a+3  2 2a+2 3a+2 a+3 3a+3 2a+3  3 2a+2 2a+1 3a+3 2a  a  0 3a+3 3a+3 2a+2 3a+2  3 2a+1 3a+1 a+1 3a 2a+1  3 a+3 a+2 2a+3 3a+3  1

generates a code of length 89 over GR(16,4) who´s minimum homogenous weight is 251.

Homogenous weight enumerator: w(x)=1x^0+1272x^251+696x^252+4428x^255+1983x^256+7056x^259+2289x^260+8220x^263+2688x^264+7992x^267+2712x^268+7644x^271+2436x^272+6588x^275+1842x^276+4164x^279+1224x^280+1560x^283+408x^284+216x^287+84x^288+12x^291+21x^292

The gray image is a code over GF(4) with n=356, k=8 and d=251.
This code was found by Heurico 1.16 in 26.6 seconds.