diff --git a/firmware/controllers/algo/engine_configuration.cpp b/firmware/controllers/algo/engine_configuration.cpp
index e3f3808b93..7171d6f048 100644
--- a/firmware/controllers/algo/engine_configuration.cpp
+++ b/firmware/controllers/algo/engine_configuration.cpp
@@ -776,6 +776,7 @@ void setDefaultConfiguration(DECLARE_ENGINE_PARAMETER_SIGNATURE) {
 	setEgoSensor(ES_14Point7_Free PASS_ENGINE_PARAMETER_SUFFIX);
 
 	engineConfiguration->globalFuelCorrection = 1;
+	engineConfiguration->adcVcc = 3.0;
 
 	engineConfiguration->map.sensor.type = MT_MPX4250;
 
diff --git a/firmware/hw_layer/algo/adc_math.h b/firmware/hw_layer/algo/adc_math.h
index 926b546ca4..0c131ac544 100644
--- a/firmware/hw_layer/algo/adc_math.h
+++ b/firmware/hw_layer/algo/adc_math.h
@@ -9,7 +9,10 @@
 #define ADC_MATH_H_
 
 // it is important that this constant is a float, not double literal
+#ifndef ADC_VCC
+// todo: migrate to engineConfiguration->adcVcc under https://github.com/rusefi/rusefi/issues/442
 #define ADC_VCC 3.0f
+#endif /* ADC_VCC */
 #define ADC_MAX_VALUE 4095
 
 #define adcToVolts(adc) (ADC_VCC / ADC_MAX_VALUE * (adc))