The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
 0  X  0  0  X  0  X  X (a+1)X (a+1)X (a+1)X (a+1)X (a+1)X (a+1)X  0  0  X  X  0  0  X  X (a+1)X (a+1)X  0  X aX (a+1)X  0  X aX (a+1)X  0  X aX (a+1)X  0  X (a+1)X aX aX aX  0  X (a+1)X aX aX aX  0  X (a+1)X  0 aX  X aX (a+1)X  0  X
 0  0  X  0 (a+1)X  X (a+1)X  0 (a+1)X (a+1)X  X  X (a+1)X  X  0  X (a+1)X  0  0  X (a+1)X  0 (a+1)X  X aX aX aX aX aX aX aX aX aX aX aX aX (a+1)X  X  0  0  X (a+1)X (a+1)X  X  0  0  X (a+1)X (a+1)X  X  0 aX (a+1)X  X  0 aX (a+1)X (a+1)X
 0  0  0  X  X  X aX (a+1)X  0  X  0  X aX aX aX (a+1)X  0 aX (a+1)X aX (a+1)X  X (a+1)X (a+1)X  0 (a+1)X  0 (a+1)X  X  X (a+1)X aX aX aX  X  0 (a+1)X  0  X aX aX aX aX (a+1)X (a+1)X  0  X (a+1)X  X  X aX (a+1)X  X aX (a+1)X  X  0 aX

generates a code of length 58 over F4[X,sigma]/(X^2) who´s minimum homogenous weight is 168.

Homogenous weight enumerator: w(x)=1x^0+48x^168+90x^172+768x^174+87x^176+21x^184+6x^188+3x^232

The gray image is a linear code over GF(4) with n=232, k=5 and d=168.
This code was found by Heurico 1.16 in 0.047 seconds.