diff --git a/components/truma_inetbox/TrumaiNetBoxApp.cpp b/components/truma_inetbox/TrumaiNetBoxApp.cpp
index 8b1ffe2..d891a6d 100644
--- a/components/truma_inetbox/TrumaiNetBoxApp.cpp
+++ b/components/truma_inetbox/TrumaiNetBoxApp.cpp
@@ -34,22 +34,19 @@ void TrumaiNetBoxApp::update() {
   if (this->master_mode_ && !this->master_discovery_started_) {
     this->master_discovery_started_ = true;
     
-    // Start targeted device discovery like CP Plus does
-    // Query known Truma device identifiers instead of full scan
+    ESP_LOGI(TAG, "Master mode: Starting discovery with CORRECT CP Plus signature 17 46 10 03");
     
-    // Query identifier 0x23 - typical for Truma heaters
-    std::vector<uint8_t> heater_query = {0xB2, 0x23, 0x17, 0x46, 0x01, 0x03};
-    this->master_send_diag_single(0x7F, heater_query);
+    // Query identifier 0x23 with CORRECT CP Plus signature (17 46 10 03)
+    std::vector<uint8_t> query_23 = {0xB2, 0x23, 0x17, 0x46, 0x10, 0x03};
+    this->master_send_diag_single(0x7F, query_23);
+    this->master_send_diag_single(0x01, query_23); // Also try direct NAD
     
-    // Query identifier 0x00 - LIN Product Identification 
-    std::vector<uint8_t> prod_id_query = {0xB2, 0x00, 0x17, 0x46, 0x00, 0x1F};
-    this->master_send_diag_single(0x7F, prod_id_query);
+    // Query identifier 0x00 with CORRECT CP Plus signature (17 46 10 03)
+    std::vector<uint8_t> query_00 = {0xB2, 0x00, 0x17, 0x46, 0x10, 0x03};
+    this->master_send_diag_single(0x7F, query_00);
+    this->master_send_diag_single(0x01, query_00); // Also try direct NAD
     
-    // Query identifier 0x00 with different device signatures
-    std::vector<uint8_t> heater_prod_query = {0xB2, 0x00, 0x17, 0x46, 0x40, 0x03}; // Heater signature
-    this->master_send_diag_single(0x7F, heater_prod_query);
-    
-    ESP_LOGI(TAG, "Master mode: Started targeted device discovery (CP Plus style)");
+    ESP_LOGI(TAG, "Master mode: Discovery sent - expecting heater response on PID 3D");
   }
 
     // Master TX scheduler (throttle to ~20ms spacing)
@@ -480,31 +477,30 @@ void TrumaiNetBoxApp::trigger_discovery() {
     return;
   }
   
-  ESP_LOGI(TAG, "=== ENHANCED DISCOVERY SEQUENCE STARTED ===");
+  ESP_LOGI(TAG, "=== FIXED DISCOVERY SEQUENCE STARTED ===");
+  ESP_LOGI(TAG, "Using correct CP Plus signature 17 46 10 03 from UDP traffic analysis");
   
-  // Try multiple NAD addresses - broadcast and specific
-  std::vector<uint8_t> nad_addresses = {0x7F, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05};
+  // Target heater NAD (seen responding as NAD 0x01 in traffic)
+  uint8_t heater_nad = 0x01;
+  
+  // Also try broadcast for completeness
+  std::vector<uint8_t> nad_addresses = {0x7F, heater_nad};
   
   for (uint8_t nad : nad_addresses) {
-    ESP_LOGI(TAG, "Trying NAD 0x%02X:", nad);
+    ESP_LOGI(TAG, "Sending discovery to NAD 0x%02X:", nad);
     
-    // 1. Query identifier 0x23 - from CP Plus log analysis
-    std::vector<uint8_t> heater_23_query = {0xB2, 0x23, 0x17, 0x46, 0x01, 0x03};
-    this->master_send_diag_single(nad, heater_23_query);
-    ESP_LOGD(TAG, "  -> Sent B2 23 query to NAD 0x%02X", nad);
+    // 1. Query identifier 0x23 with CORRECT CP Plus signature (17 46 10 03)
+    std::vector<uint8_t> query_23 = {0xB2, 0x23, 0x17, 0x46, 0x10, 0x03};
+    this->master_send_diag_single(nad, query_23);
+    ESP_LOGI(TAG, "  -> B2 23 17 46 10 03 (CP Plus sig)");
     
-    // 2. Query identifier 0x00 with heater signature (17 46 40 03)
-    std::vector<uint8_t> heater_00_query = {0xB2, 0x00, 0x17, 0x46, 0x40, 0x03};
-    this->master_send_diag_single(nad, heater_00_query);
-    ESP_LOGD(TAG, "  -> Sent B2 00 heater sig query to NAD 0x%02X", nad);
-    
-    // 3. Query identifier 0x00 with CP Plus signature (as reference)
-    std::vector<uint8_t> cpplus_00_query = {0xB2, 0x00, 0x17, 0x46, 0x00, 0x04};
-    this->master_send_diag_single(nad, cpplus_00_query);
-    ESP_LOGD(TAG, "  -> Sent B2 00 CP Plus sig query to NAD 0x%02X", nad);
+    // 2. Query identifier 0x00 with CORRECT CP Plus signature (17 46 10 03) 
+    std::vector<uint8_t> query_00 = {0xB2, 0x00, 0x17, 0x46, 0x10, 0x03};
+    this->master_send_diag_single(nad, query_00);
+    ESP_LOGI(TAG, "  -> B2 00 17 46 10 03 (CP Plus sig)");
   }
   
-  ESP_LOGI(TAG, "=== DISCOVERY SEQUENCE COMPLETED - Monitor PID 3D for responses ===");
+  ESP_LOGI(TAG, "=== DISCOVERY COMPLETED - HEATER SHOULD RESPOND ON PID 3D ===");
 }
 
 } }