diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 1c20657..47c16c2 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -451,8 +451,8 @@
 	}
 }
 
-friend function f_l1_tune(L1CTL_PT L1CTL) {
-	f_L1CTL_FBSB(L1CTL, { false, mp_trx0_arfcn }, CCCH_MODE_COMBINED, mp_rxlev_exp);
+friend function f_l1_tune(L1CTL_PT L1CTL, L1ctlCcchMode ccch_mode := CCCH_MODE_COMBINED) {
+	f_L1CTL_FBSB(L1CTL, { false, mp_trx0_arfcn }, ccch_mode, mp_rxlev_exp);
 }
 
 private function f_trxc_connect() runs on ConnHdlr {