diff --git a/ns/NS_Tests.ttcn b/ns/NS_Tests.ttcn
index 105d397..8b321ff 100644
--- a/ns/NS_Tests.ttcn
+++ b/ns/NS_Tests.ttcn
@@ -131,6 +131,7 @@
 
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 testcase TC_tx_reset_tx_alive() runs on RAW_Test_CT {
@@ -145,6 +146,7 @@
 
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 testcase TC_tx_reset_rx_alive() runs on RAW_Test_CT {
@@ -160,6 +162,7 @@
 
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.2.1 transmit a UNIT DATA over a BLOCKED NSVC when ttcn3 blocked it
@@ -227,6 +230,7 @@
 	f_outgoing_ns_unblock();
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.2 tx unblock retries
@@ -254,6 +258,7 @@
 	f_outgoing_ns_unblock();
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.2 block procedure
@@ -318,6 +323,7 @@
 testcase TC_tx_block_by_vty() runs on RAW_Test_CT {
 	tx_block_by_vty(30.0);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.2 block precedure by vty and reset the NSVC.
@@ -336,6 +342,7 @@
 	[] T.timeout { setverdict(pass); }
 	}
 	deactivate(d);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.4.1 ignore unexpected NS_ALIVE ACK */
@@ -347,6 +354,7 @@
 	f_fails_except_reset();
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.3.1 NS_RESET with wrong nsei */
@@ -359,6 +367,7 @@
 	f_fails_except_reset();
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.3.1 NS_RESET with wrong nsvci */
@@ -371,6 +380,7 @@
 	f_fails_except_reset();
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.3.1 NS_RESET with wrong nsvci + nsei */
@@ -383,6 +393,7 @@
 	f_fails_except_reset();
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.3.1 NS_RESET_ACK with wrong nsei */
@@ -395,6 +406,7 @@
 	f_fails_except_reset();
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.3.1 NS_RESET_ACK with wrong nsvci */
@@ -407,6 +419,7 @@
 	f_fails_except_reset();
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.3.1 NS_RESET_ACK with wrong nsvci + nsei */
@@ -419,6 +432,7 @@
 	f_fails_except_reset();
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.3.1 ignore unexpected NS_RESET_ACK after NS_RESET+ALIVE */
@@ -439,6 +453,7 @@
 	f_ensure_no_ns(answer_alive := true, tout := 15.0);
 	setverdict(pass);
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.3 NS_RESET retries */
@@ -460,6 +475,7 @@
 	}
 
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 behave RESET_ACK got dropped
@@ -493,6 +509,7 @@
 	}
 
 	f_sleep(1.0);
+	f_clean_ns_codec();
 }
 
 /* 48.016 7.4 test procedure for frame relay with a single nsvci */
@@ -526,10 +543,12 @@
 
 testcase TC_alive_retries_single_reset() runs on RAW_Test_CT {
 	f_alive_retries_single(reset := true);
+	f_clean_ns_codec();
 }
 
 testcase TC_alive_retries_single_no_resp() runs on RAW_Test_CT {
 	f_alive_retries_single(reset := false);
+	f_clean_ns_codec();
 }
 
 /* 48.016 SNS test cases */