Show us the line that sets up @icodes. If, as you say, it is
@icodes="CEN01-SJU1-022102A CEN02-MEX1-022702P CTE01-SJU1-022202A CTE02-MEX1-022802P";
then it only contains a single element. To make that an array, do something like
@icodes=qw(CEN01-SJU1-022102A CEN02-MEX1-022702P CTE01-SJU1-022202A CTE02-MEX1-022802P);