diff --git a/chassis_state_manager.cpp b/chassis_state_manager.cpp
index 8c3f7c0..0215535 100644
--- a/chassis_state_manager.cpp
+++ b/chassis_state_manager.cpp
@@ -228,9 +228,9 @@
 bool Chassis::determineStatusOfUPSPower()
 {
     // Find all implementations of the UPower interface
-    auto mapper = bus.new_method_call(ObjectMapper::default_service,
-                                      ObjectMapper::instance_path,
-                                      ObjectMapper::interface, "GetSubTree");
+    auto mapper = bus.new_method_call(
+        ObjectMapper::default_service, ObjectMapper::instance_path,
+        ObjectMapper::interface, ObjectMapper::method_names::get_sub_tree);
 
     mapper.append("/", 0, std::vector<std::string>({UPowerDevice::interface}));
 
@@ -335,9 +335,9 @@
 bool Chassis::determineStatusOfPSUPower()
 {
     // Find all implementations of the PowerSystemInputs interface
-    auto mapper = bus.new_method_call(ObjectMapper::default_service,
-                                      ObjectMapper::instance_path,
-                                      ObjectMapper::interface, "GetSubTree");
+    auto mapper = bus.new_method_call(
+        ObjectMapper::default_service, ObjectMapper::instance_path,
+        ObjectMapper::interface, ObjectMapper::method_names::get_sub_tree);
 
     mapper.append("/", 0,
                   std::vector<std::string>(