diff --git a/libraries/AP_EFI/AP_EFI_Serial_MS.cpp b/libraries/AP_EFI/AP_EFI_Serial_MS.cpp
index e37300ae4f..4f70b2466c 100644
--- a/libraries/AP_EFI/AP_EFI_Serial_MS.cpp
+++ b/libraries/AP_EFI/AP_EFI_Serial_MS.cpp
@@ -110,12 +110,12 @@ bool AP_EFI_Serial_MS::read_incoming_realtime_data()
             case MAT_MSB:
                 temp_float = (float)((data << 8) + read_byte_CRC32())/10.0f;
                 offset++;
-                internal_state.intake_manifold_temperature = f_to_k(temp_float);
+                internal_state.intake_manifold_temperature = degF_to_Kelvin(temp_float);
                 break;
             case CHT_MSB:
                 temp_float = (float)((data << 8) + read_byte_CRC32())/10.0f;
                 offset++;
-                internal_state.cylinder_status[0].cylinder_head_temperature = f_to_k(temp_float);
+                internal_state.cylinder_status[0].cylinder_head_temperature = degF_to_Kelvin(temp_float);
                 break;
             case TPS_MSB:
                 temp_float = (float)((data << 8) + read_byte_CRC32())/10.0f;
diff --git a/libraries/AP_EFI/AP_EFI_Serial_MS.h b/libraries/AP_EFI/AP_EFI_Serial_MS.h
index b78608a883..f72701d3b6 100644
--- a/libraries/AP_EFI/AP_EFI_Serial_MS.h
+++ b/libraries/AP_EFI/AP_EFI_Serial_MS.h
@@ -36,8 +36,7 @@ private:
     void send_request(uint8_t table, uint16_t first_offset, uint16_t last_offset);
     uint8_t read_byte_CRC32();
     uint32_t CRC32_compute_byte(uint32_t inCrc32, uint8_t data);
-    float f_to_k(float temp_f) { return (temp_f + 459.67f) * 0.55556f; };
-    
+
     // Serial Protocol Variables
     uint32_t checksum;
     uint8_t step;