diff --git a/custom_components/tpms_ble/sensor.py b/custom_components/tpms_ble/sensor.py
index 24f2163..e66dd23 100644
--- a/custom_components/tpms_ble/sensor.py
+++ b/custom_components/tpms_ble/sensor.py
@@ -62,6 +62,7 @@
     TPMSSensor.TIMESTAMP: SensorEntityDescription(
         key=TPMSSensor.TIMESTAMP,
         device_class=SensorDeviceClass.TIMESTAMP,
+        entity_category=EntityCategory.DIAGNOSTIC,
         icon="mdi:clock-time-four-outline",
     ),
 }