diff --git a/lib/modem-commands.js b/lib/modem-commands.js
index 1b3b554..122f9ae 100644
--- a/lib/modem-commands.js
+++ b/lib/modem-commands.js
@@ -151,5 +151,5 @@ exports.queryIMEIAndIMSI = async function queryIMEIAndIMSI() {
     await this.queryIMEI(MUTEX_SUBCOMMAND);
     await this.queryIMSI(MUTEX_SUBCOMMAND);
 
-    await mutex.unlock(MUTEX_SUBCOMMAND, 'queryIMEIAndIMSI');
+    await mutex.unlock(MUTEX_COMMAND, 'queryIMEIAndIMSI');
 };