diff --git a/radio/1.3/IRadioResponse.hal b/radio/1.3/IRadioResponse.hal
index c3bbe65..85085e2 100644
--- a/radio/1.3/IRadioResponse.hal
+++ b/radio/1.3/IRadioResponse.hal
@@ -44,6 +44,9 @@
      *   RadioError:NONE
      *   RadioError:RADIO_NOT_AVAILABLE
      *   RadioError:MODEM_ERR
+     *   RadioError:INVALID_STATE: this is for the case that the API is called in a single-sim
+     *              mode, or when there is only one modem available, as this API should only
+     *              be called in multi sim status.
      */
     oneway enableModemResponse(RadioResponseInfo info);
 
diff --git a/radio/1.3/vts/functional/radio_hidl_hal_api.cpp b/radio/1.3/vts/functional/radio_hidl_hal_api.cpp
index 6c52ed7..7fb8995 100644
--- a/radio/1.3/vts/functional/radio_hidl_hal_api.cpp
+++ b/radio/1.3/vts/functional/radio_hidl_hal_api.cpp
@@ -35,7 +35,7 @@
           toString(radioRsp_v1_3->rspInfo.error).c_str());
     ASSERT_TRUE(CheckAnyOfErrors(radioRsp_v1_3->rspInfo.error,
                                  {RadioError::NONE, RadioError::RADIO_NOT_AVAILABLE,
-                                  RadioError::MODEM_ERR, RadioError::REQUEST_NOT_SUPPORTED}));
+                                  RadioError::MODEM_ERR, RadioError::INVALID_STATE}));
 
     // checking if getModemStackStatus returns true, as modem was enabled above
     if (RadioError::NONE == radioRsp_v1_3->rspInfo.error) {
@@ -52,7 +52,7 @@
               toString(radioRsp_v1_3->rspInfo.error).c_str());
         ASSERT_TRUE(CheckAnyOfErrors(radioRsp_v1_3->rspInfo.error,
                                      {RadioError::NONE, RadioError::RADIO_NOT_AVAILABLE,
-                                      RadioError::MODEM_ERR, RadioError::REQUEST_NOT_SUPPORTED}));
+                                      RadioError::MODEM_ERR, RadioError::INVALID_STATE}));
         // verify that enableModem did set isEnabled correctly
         EXPECT_EQ(true, radioRsp_v1_3->isModemEnabled);
     }