diff --git a/src/tcpcheck.c b/src/tcpcheck.c
index 9610760d7..e57b05fc6 100644
--- a/src/tcpcheck.c
+++ b/src/tcpcheck.c
@@ -1304,7 +1304,7 @@ enum tcpcheck_eval_ret tcpcheck_eval_send(struct check *check, struct tcpcheck_r
 	}
 
 	/* Data already pending in the output buffer, send them now */
-	if (b_data(&check->bo)) {
+	if ((IS_HTX_CONN(conn) && !htx_is_empty(htxbuf(&check->bo))) || (!IS_HTX_CONN(conn) && b_data(&check->bo))) {
 		TRACE_DEVEL("Data still pending, try to send it now", CHK_EV_TCPCHK_SND|CHK_EV_TX_DATA, check);
 		goto do_send;
 	}
@@ -1448,7 +1448,7 @@ enum tcpcheck_eval_ret tcpcheck_eval_send(struct check *check, struct tcpcheck_r
 			goto out;
 		}
 	}
-	if ((IS_HTX_CONN(conn) && !htx_is_empty(htxbuf(&check->bo))) || b_data(&check->bo)) {
+	if ((IS_HTX_CONN(conn) && !htx_is_empty(htxbuf(&check->bo))) || (!IS_HTX_CONN(conn) && b_data(&check->bo))) {
 		cs->conn->mux->subscribe(cs, SUB_RETRY_SEND, &check->wait_list);
 		ret = TCPCHK_EVAL_WAIT;
 		TRACE_DEVEL("data not fully sent, wait", CHK_EV_TCPCHK_SND|CHK_EV_TX_DATA, check);