diff --git a/monitor/tach_sensor.cpp b/monitor/tach_sensor.cpp
index 0e30a10..605aff5 100644
--- a/monitor/tach_sensor.cpp
+++ b/monitor/tach_sensor.cpp
@@ -209,8 +209,15 @@
 
 void TachSensor::startTimer(TimerMode mode)
 {
+    using namespace std::chrono;
+
     if (!timerRunning() || mode != _timerMode)
     {
+        log<level::INFO>(
+            fmt::format("Start timer({}) on tach sensor {}. [delay = {}s]",
+                        mode, _name,
+                        duration_cast<seconds>(getDelay(mode)).count())
+                .c_str());
         _timer.restartOnce(getDelay(mode));
         _timerMode = mode;
     }
diff --git a/monitor/tach_sensor.hpp b/monitor/tach_sensor.hpp
index 4a09f17..703605a 100644
--- a/monitor/tach_sensor.hpp
+++ b/monitor/tach_sensor.hpp
@@ -1,5 +1,8 @@
 #pragma once
 
+#include <fmt/format.h>
+
+#include <phosphor-logging/log.hpp>
 #include <sdbusplus/bus.hpp>
 #include <sdbusplus/server.hpp>
 #include <sdeventplus/clock.hpp>
@@ -247,6 +250,9 @@
      */
     inline void stopTimer()
     {
+        phosphor::logging::log<phosphor::logging::level::INFO>(
+            fmt::format("Stop running timer on tach sensor {}.", _name)
+                .c_str());
         _timer.setEnabled(false);
     }