The generator matrix

 1  0  1  1 X^2+X  1  1  1  X  1  1 X^3+X^2  1 X^2  1  1  1  1
 0  1  1 X^2+X  1 X^3+X+1 X^3+X^2+1 X^2  1  X X^3+X^2+X+1  1 X^3+X^2+X  X X^3+X^2+X X^3+X  X X+1
 0  0  X  0 X^3 X^2 X^3+X^2  X  X X^3+X X^2+X X^3+X^2+X X^3+X  X X^3+X^2+X X^3 X^3+X^2 X^3
 0  0  0 X^3 X^3  0 X^3 X^3 X^3  0 X^3  0 X^3 X^3  0  0 X^3 X^3

generates a code of length 18 over Z2[X]/(X^4) who´s minimum homogenous weight is 15.

Homogenous weight enumerator: w(x)=1x^0+160x^15+542x^16+752x^17+1237x^18+736x^19+506x^20+112x^21+10x^22+32x^23+7x^24+1x^26

The gray image is a linear code over GF(2) with n=144, k=12 and d=60.
This code was found by Heurico 1.16 in 0.094 seconds.