diff --git a/system/diagnostic_graph_aggregator/src/common/graph/graph.hpp b/system/diagnostic_graph_aggregator/src/common/graph/graph.hpp
index 0e64f25860fda..14a27dae9a539 100644
--- a/system/diagnostic_graph_aggregator/src/common/graph/graph.hpp
+++ b/system/diagnostic_graph_aggregator/src/common/graph/graph.hpp
@@ -34,7 +34,6 @@ class Graph
   void update(const rclcpp::Time & stamp);  // cppcheck-suppress functionConst
   bool update(const rclcpp::Time & stamp, const DiagnosticStatus & status);
   const auto & nodes() const { return nodes_; }
-  const auto & diags() const { return diags_; }
   const auto & units() const { return units_; }
   DiagGraphStruct create_struct(const rclcpp::Time & stamp) const;
   DiagGraphStatus create_status(const rclcpp::Time & stamp) const;