diff --git a/sys/net/application_layer/nanocoap/sock.c b/sys/net/application_layer/nanocoap/sock.c
index 05a5a838f9..7a0ee5627b 100644
--- a/sys/net/application_layer/nanocoap/sock.c
+++ b/sys/net/application_layer/nanocoap/sock.c
@@ -294,7 +294,7 @@ ssize_t nanocoap_sock_request_cb(nanocoap_sock_t *sock, coap_pkt_t *pkt,
                 _send_ack(sock, pkt);
                 /* fall-through */
             case COAP_TYPE_ACK:
-                if (cb && coap_get_code(pkt) == COAP_CODE_EMPTY) {
+                if (cb && coap_get_code_raw(pkt) == COAP_CODE_EMPTY) {
                     /* empty ACK, wait for separate response */
                     state = STATE_RESPONSE_RCVD;
                     deadline = _deadline_from_interval(CONFIG_COAP_SEPARATE_RESPONSE_TIMEOUT_MS