diff --git a/asm/field_map_obj.s b/asm/field_map_obj.s
index 927625ff3a..895607305d 100644
--- a/asm/field_map_obj.s
+++ b/asm/field_map_obj.s
@@ -5,89 +5,6 @@
 
 	.text
 
-	thumb_func_start GetFieldObjectIdByXYZ
-@ u8 GetFieldObjectIdByXYZ(u16 x, u16 y, u8 z)
-GetFieldObjectIdByXYZ: @ 808EC78
-	push {r4-r7,lr}
-	mov r7, r8
-	push {r7}
-	lsls r0, 16
-	lsrs r7, r0, 16
-	lsls r1, 16
-	lsrs r6, r1, 16
-	lsls r2, 24
-	lsrs r5, r2, 24
-	movs r4, 0
-	ldr r0, =gMapObjects
-	mov r8, r0
-_0808EC90:
-	lsls r0, r4, 3
-	adds r0, r4
-	lsls r0, 2
-	mov r2, r8
-	adds r1, r0, r2
-	ldrb r0, [r1]
-	lsls r0, 31
-	cmp r0, 0
-	beq _0808ECC8
-	movs r2, 0x10
-	ldrsh r0, [r1, r2]
-	cmp r0, r7
-	bne _0808ECC8
-	movs r2, 0x12
-	ldrsh r0, [r1, r2]
-	cmp r0, r6
-	bne _0808ECC8
-	adds r0, r1, 0
-	adds r1, r5, 0
-	bl FieldObjectDoesZCoordMatch
-	lsls r0, 24
-	cmp r0, 0
-	beq _0808ECC8
-	adds r0, r4, 0
-	b _0808ECD4
-	.pool
-_0808ECC8:
-	adds r0, r4, 0x1
-	lsls r0, 24
-	lsrs r4, r0, 24
-	cmp r4, 0xF
-	bls _0808EC90
-	movs r0, 0x10
-_0808ECD4:
-	pop {r3}
-	mov r8, r3
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	thumb_func_end GetFieldObjectIdByXYZ
-
-	thumb_func_start FieldObjectDoesZCoordMatch
-@ bool8 FieldObjectDoesZCoordMatch(struct npc_state *fieldObject)
-FieldObjectDoesZCoordMatch: @ 808ECE0
-	push {lr}
-	lsls r1, 24
-	lsrs r1, 24
-	ldrb r2, [r0, 0xB]
-	movs r0, 0xF
-	ands r0, r2
-	cmp r0, 0
-	beq _0808ED00
-	cmp r1, 0
-	beq _0808ED00
-	lsls r0, r2, 28
-	lsrs r0, 28
-	cmp r0, r1
-	beq _0808ED00
-	movs r0, 0
-	b _0808ED02
-_0808ED00:
-	movs r0, 0x1
-_0808ED02:
-	pop {r1}
-	bx r1
-	thumb_func_end FieldObjectDoesZCoordMatch
-
 	thumb_func_start UpdateFieldObjectsForCameraUpdate
 @ void UpdateFieldObjectsForCameraUpdate(u16 movingCameraOffsetX, u16 movingCameraOffsetY)
 UpdateFieldObjectsForCameraUpdate: @ 808ED08
diff --git a/src/field_map_obj.c b/src/field_map_obj.c
index ced0ecb27e..a48a2506e8 100644
--- a/src/field_map_obj.c
+++ b/src/field_map_obj.c
@@ -47,6 +47,7 @@ static void SetPlayerAvatarFieldObjectIdAndObjectId(u8, u8);
 static u8 sub_808E8F4(const struct SpritePalette *);
 static u8 FindFieldObjectPaletteIndexByTag(u16);
 static void sub_808EAB0(u16, u8);
+static bool8 FieldObjectDoesZCoordMatch(struct MapObject *, u8);
 
 // ROM data
 
@@ -1304,3 +1305,27 @@ void UpdateFieldObjectCoordsForCameraUpdate(void)
     }
 }
 
+u8 GetFieldObjectIdByXYZ(u16 x, u16 y, u8 z)
+{
+    u8 i;
+    for (i = 0; i < NUM_FIELD_OBJECTS; i ++)
+    {
+        if (gMapObjects[i].active)
+        {
+            if (gMapObjects[i].coords2.x == x && gMapObjects[i].coords2.y == y && FieldObjectDoesZCoordMatch(&gMapObjects[i], z))
+            {
+                return i;
+            }
+        }
+    }
+    return NUM_FIELD_OBJECTS;
+}
+
+static bool8 FieldObjectDoesZCoordMatch(struct MapObject *mapObject, u8 z)
+{
+    if (mapObject->mapobj_unk_0B_0 != 0 && z != 0 && mapObject->mapobj_unk_0B_0 != z)
+    {
+        return FALSE;
+    }
+    return TRUE;
+}