diff --git a/recipes-connectivity/wwan-config/wwan-config/wwan-config@.service b/recipes-connectivity/wwan-config/wwan-config/wwan-config@.service
index f0e5c49..5dc1421 100644
--- a/recipes-connectivity/wwan-config/wwan-config/wwan-config@.service
+++ b/recipes-connectivity/wwan-config/wwan-config/wwan-config@.service
@@ -9,6 +9,9 @@ Restart=on-failure
 Nice=-20
 # Start time may include power cycles and start of ModemManager
 TimeoutStartSec=180
+# The default kill mode is killing the subprocesses created by the "os.system"
+# calls used to stop ModemManager when handling the kill signal.
+KillMode=mixed
 
 [Install]
 RequiredBy=multi-user.target