diff --git a/src/HwmonTempSensor.cpp b/src/HwmonTempSensor.cpp
index 5222b04..cf8ee10 100644
--- a/src/HwmonTempSensor.cpp
+++ b/src/HwmonTempSensor.cpp
@@ -119,6 +119,11 @@
             errCount++;
         }
     }
+    else if (readState == PowerState::on && !isPowerOn())
+    {
+        errCount = 0;
+        updateValue(std::numeric_limits<double>::quiet_NaN());
+    }
     else
     {
         errCount++;