diff --git a/firmware/rusefi.cpp b/firmware/rusefi.cpp
index acdd2e3820..924d8b950e 100644
--- a/firmware/rusefi.cpp
+++ b/firmware/rusefi.cpp
@@ -111,6 +111,7 @@
 #include "flash_main.h"
 #include "algo.h"
 #include "custom_engine.h"
+#include "engine_math.h"
 
 #if EFI_HD44780_LCD
 #include "lcd_HD44780.h"