4-Digit Locker Key Combination

Let digits be $a, b, c, d$. All positive ($1-9$), distinct, $d < a, b, c$, $a \le 3$, and $b/c = a \implies b = ac$. Since $a \le 3$ and $a > d$, $a$ cannot be 1. Thus $a=2$ or $a=3$. Case 1: $a=2 \implies d=1$. $b = 2c$. If $c=3 \implies b=6$, code is $2631$. If $c=4 \implies b=8$, code is $2841$. Case 2: $a=3 \implies d=1$ or $d=2$. $b = 3c$. If $d=1 \implies c=2 \implies b=6$, code is $3621$. If $d=2$, no integer $c$ works with distinct non-repeating digits. Total combinations = 3.