diff --git a/firmware/controllers/algo/engine.h b/firmware/controllers/algo/engine.h
index a9171af748..08d6e84f0e 100644
--- a/firmware/controllers/algo/engine.h
+++ b/firmware/controllers/algo/engine.h
@@ -39,7 +39,7 @@ public:
 	int fakeAdcValues[MOCK_ADC_SIZE];
 
 	void setMockVoltage(int hwChannel, float voltage);
-	int getMockAdcValue(int hwChannel);
+	int getMockAdcValue(int hwChannel) const;
 };
 
 #define MAX_INJECTION_OUTPUT_COUNT INJECTION_PIN_COUNT
@@ -67,8 +67,7 @@ class ThermistorMath {
 public:
 	void setConfig(thermistor_conf_s *config);
 	void prepareThermistorCurve(thermistor_conf_s *tc);
-	bool isLinearSensor();
-	float getKelvinTemperatureByResistance(float resistance);
+	float getKelvinTemperatureByResistance(float resistance) const;
 	float s_h_a = 0;
 	float s_h_b = 0;
 	float s_h_c = 0;
@@ -137,7 +136,7 @@ class WarningCodeState {
 public:
 	WarningCodeState();
 	void addWarningCode(obd_code_e code);
-	bool isWarningNow(efitimesec_t now, bool forIndicator DECLARE_ENGINE_PARAMETER_SUFFIX);
+	bool isWarningNow(efitimesec_t now, bool forIndicator DECLARE_ENGINE_PARAMETER_SUFFIX) const;
 	void clear();
 	int warningCounter;
 	int lastErrorCode;
diff --git a/firmware/controllers/algo/engine2.cpp b/firmware/controllers/algo/engine2.cpp
index d01182afc0..13957b173f 100644
--- a/firmware/controllers/algo/engine2.cpp
+++ b/firmware/controllers/algo/engine2.cpp
@@ -58,7 +58,7 @@ void WarningCodeState::addWarningCode(obd_code_e code) {
 /**
  * @param forIndicator if we want to retrieving value for TS indicator, this case a minimal period is applued
  */
-bool WarningCodeState::isWarningNow(efitimesec_t now, bool forIndicator DECLARE_ENGINE_PARAMETER_SUFFIX) {
+bool WarningCodeState::isWarningNow(efitimesec_t now, bool forIndicator DECLARE_ENGINE_PARAMETER_SUFFIX) const {
 	int period = forIndicator ? maxI(3, engineConfiguration->warningPeriod) : engineConfiguration->warningPeriod;
 	return absI(now - timeOfPreviousWarning) < period;
 }
@@ -229,7 +229,7 @@ SensorsState::SensorsState() {
 	reset();
 }
 
-int MockAdcState::getMockAdcValue(int hwChannel) {
+int MockAdcState::getMockAdcValue(int hwChannel) const {
 	return fakeAdcValues[hwChannel];
 }
 
diff --git a/firmware/controllers/sensors/thermistors.cpp b/firmware/controllers/sensors/thermistors.cpp
index efe925cdda..b6aaccd796 100644
--- a/firmware/controllers/sensors/thermistors.cpp
+++ b/firmware/controllers/sensors/thermistors.cpp
@@ -47,7 +47,7 @@ float getVoutInVoltageDividor(float Vin, float r1, float r2) {
 	return r2 * Vin / (r1 + r2);
 }
 
-float ThermistorMath::getKelvinTemperatureByResistance(float resistance) {
+float ThermistorMath::getKelvinTemperatureByResistance(float resistance) const {
 	if (resistance <= 0) {
 		//warning("Invalid resistance in getKelvinTemperature=", resistance);
 		return 0.0f;
diff --git a/firmware/controllers/trigger/trigger_decoder.cpp b/firmware/controllers/trigger/trigger_decoder.cpp
index 1d48f6e840..ea0e74ed87 100644
--- a/firmware/controllers/trigger/trigger_decoder.cpp
+++ b/firmware/controllers/trigger/trigger_decoder.cpp
@@ -120,7 +120,7 @@ efitime_t TriggerState::getTotalEventCounter() {
 	return totalEventCountBase + currentCycle.current_index;
 }
 
-int TriggerState::getTotalRevolutionCounter() {
+int TriggerState::getTotalRevolutionCounter() const {
 	return totalRevolutionCounter;
 }
 
@@ -263,7 +263,7 @@ void TriggerState::reset() {
 	isFirstEvent = true;
 }
 
-int TriggerState::getCurrentIndex() {
+int TriggerState::getCurrentIndex() const {
 	return currentCycle.current_index;
 }
 
@@ -271,7 +271,7 @@ void TriggerState::incrementTotalEventCounter() {
 	totalRevolutionCounter++;
 }
 
-bool TriggerState::isEvenRevolution() {
+bool TriggerState::isEvenRevolution() const {
 	return totalRevolutionCounter & 1;
 }
 
diff --git a/firmware/controllers/trigger/trigger_decoder.h b/firmware/controllers/trigger/trigger_decoder.h
index 34db4c155e..c0a458ef49 100644
--- a/firmware/controllers/trigger/trigger_decoder.h
+++ b/firmware/controllers/trigger/trigger_decoder.h
@@ -50,12 +50,12 @@ public:
 	/**
 	 * current trigger processing index, between zero and #size
 	 */
-	int getCurrentIndex();
-	int getTotalRevolutionCounter();
+	int getCurrentIndex() const;
+	int getTotalRevolutionCounter() const;
 	/**
 	 * this is important for crank-based virtual trigger and VVT magic
 	 */
-	bool isEvenRevolution();
+	bool isEvenRevolution() const;
 	void incrementTotalEventCounter();
 	efitime_t getTotalEventCounter();
 	efitime_t getStartOfRevolutionIndex();