The generator matrix

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

generates a code of length 18 over Z4[X]/(X^3+2,2X) who´s minimum homogenous weight is 12.

Homogenous weight enumerator: w(x)=1x^0+158x^12+654x^13+3042x^14+10416x^15+27209x^16+54422x^17+70016x^18+54704x^19+27686x^20+10106x^21+2802x^22+736x^23+146x^24+34x^25+12x^26

The gray image is a code over GF(2) with n=144, k=18 and d=48.
This code was found by Heurico 1.16 in 87.7 seconds.