diff --git a/monitor/system.hpp b/monitor/system.hpp
index 6725b00..a690567 100644
--- a/monitor/system.hpp
+++ b/monitor/system.hpp
@@ -37,6 +37,10 @@
 
 using json = nlohmann::json;
 
+// Mapping from service name to sensor
+using SensorMapType =
+    std::map<std::string, std::set<std::shared_ptr<TachSensor>>>;
+
 class System
 {
   public:
@@ -164,6 +168,11 @@
     ThermalAlertObject _thermalAlert;
 
     /**
+     * @brief The tach sensors D-Bus match objects
+     */
+    std::vector<std::unique_ptr<sdbusplus::bus::match::match>> _sensorMatch;
+
+    /**
      * @brief If start() has been called
      */
     bool _started = false;
@@ -177,6 +186,14 @@
     json captureSensorData();
 
     /**
+     * @brief Builds a mapping for sensors to be identified
+     *        for a given service name.
+     *
+     * @return a map of service_name->[sensor1,sensor2...]
+     */
+    SensorMapType buildNameOwnerChangedMap() const;
+
+    /**
      * @brief Retrieve the configured trust groups
      *
      * @param[in] jsonObj - JSON object to parse from
@@ -216,6 +233,16 @@
     void updateFanHealth(const Fan& fan);
 
     /**
+     * @brief callback when a tach sensor signal goes offline
+     *
+     * @param[in] msg - D-Bus message containing details (inc. service name)
+     *
+     * @param[in] sensorMap - map providing sensor access for each service
+     */
+    void tachSignalOffline(sdbusplus::message::message& msg,
+                           const SensorMapType& sensorMap);
+
+    /**
      * @brief The function that runs when the power state changes
      *
      * @param[in] powerStateOn - If power is now on or not