diff --git a/speeduino/corrections.cpp b/speeduino/corrections.cpp
index 8112ea28cf..769c90892e 100644
--- a/speeduino/corrections.cpp
+++ b/speeduino/corrections.cpp
@@ -33,27 +33,27 @@ There are 2 top level functions that call more detailed corrections for Fuel and
 
 #define IGN_IDLE_THRESHOLD 200 //RPM threshold (below CL idle target) for when ign based idle control will engage
 
-long PID_O2, PID_output, PID_AFRTarget;
+static long PID_O2, PID_output, PID_AFRTarget;
 /** Instance of the PID object in case that algorithm is used (Always instantiated).
 * Needs to be global as it maintains state outside of each function call.
 * Comes from Arduino (?) PID library.
 */
-PID egoPID(&PID_O2, &PID_output, &PID_AFRTarget, configPage6.egoKP, configPage6.egoKI, configPage6.egoKD, REVERSE);
+static PID egoPID(&PID_O2, &PID_output, &PID_AFRTarget, configPage6.egoKP, configPage6.egoKI, configPage6.egoKD, REVERSE);
 
-byte activateMAPDOT; //The mapDOT value seen when the MAE was activated. 
-byte activateTPSDOT; //The tpsDOT value seen when the MAE was activated.
+static byte activateMAPDOT; //The mapDOT value seen when the MAE was activated. 
+static byte activateTPSDOT; //The tpsDOT value seen when the MAE was activated.
 
-bool idleAdvActive = false;
+static bool idleAdvActive = false;
 uint16_t AFRnextCycle;
-unsigned long knockStartTime;
-uint8_t knockLastRecoveryStep;
+static unsigned long knockStartTime;
+static uint8_t knockLastRecoveryStep;
 //int16_t knockWindowMin; //The current minimum crank angle for a knock pulse to be valid
 //int16_t knockWindowMax;//The current maximum crank angle for a knock pulse to be valid
-uint8_t aseTaper;
-uint8_t dfcoDelay;
-uint8_t idleAdvTaper;
-uint8_t crankingEnrichTaper;
-uint8_t dfcoTaper;
+static uint8_t aseTaper;
+uint8_t dfcoDelay; // Non-static for unit testing
+static uint8_t idleAdvTaper;
+static uint8_t crankingEnrichTaper;
+uint8_t dfcoTaper; // Non-static for unit testing
 
 /** Initialise instances and vars related to corrections (at ECU boot-up).
  */
@@ -369,7 +369,7 @@ uint16_t correctionAccel(void)
               //If CLT is less than taper min temp, apply full modifier on top of accelValue
               if ( currentStatus.coolant <= (int)(configPage2.aeColdTaperMin - CALIBRATION_TEMPERATURE_OFFSET) )
               {
-                uint16_t accelValue_uint = percentage(configPage2.aeColdPct, (uint16_t)accelValue);
+                uint16_t accelValue_uint = (uint16_t)percentage(configPage2.aeColdPct, (uint16_t)accelValue);
                 accelValue = (int16_t) accelValue_uint;
               }
               //If CLT is between taper min and max, taper the modifier value and apply it on top of accelValue
@@ -377,7 +377,7 @@ uint16_t correctionAccel(void)
               {
                 int16_t taperRange = (int16_t) configPage2.aeColdTaperMax - configPage2.aeColdTaperMin;
                 int16_t taperPercent = (int)((currentStatus.coolant + CALIBRATION_TEMPERATURE_OFFSET - configPage2.aeColdTaperMin) * 100) / taperRange;
-                int16_t coldPct = (int16_t) 100 + percentage((uint8_t) (100U-taperPercent), (configPage2.aeColdPct-100U) );
+                int16_t coldPct = (int16_t) 100 + (int16_t)percentage((uint8_t) (100U-taperPercent), (configPage2.aeColdPct-100U) );
                 uint16_t accelValue_uint = (uint16_t) accelValue * coldPct / 100; //Potential overflow (if AE is large) without using uint16_t (percentage() may overflow)
                 accelValue = (int16_t) accelValue_uint;
               }
@@ -441,8 +441,8 @@ uint16_t correctionAccel(void)
               else
               {
                 int16_t taperRange = (int16_t) configPage2.aeColdTaperMax - configPage2.aeColdTaperMin;
-                int16_t taperPercent = (int)((currentStatus.coolant + CALIBRATION_TEMPERATURE_OFFSET - configPage2.aeColdTaperMin) * 100) / taperRange;
-                int16_t coldPct = (int16_t)100 + percentage((uint8_t) (100 - taperPercent), (uint16_t)(configPage2.aeColdPct-100) );
+                uint16_t taperPercent = (int)((currentStatus.coolant + CALIBRATION_TEMPERATURE_OFFSET - configPage2.aeColdTaperMin) * 100) / taperRange;
+                uint16_t coldPct = 100U + (uint16_t)percentage((uint8_t) (100U - taperPercent), configPage2.aeColdPct-100U);
                 uint16_t accelValue_uint = (uint16_t) accelValue * coldPct / 100; //Potential overflow (if AE is large) without using uint16_t
                 accelValue = (int16_t) accelValue_uint;
               }
diff --git a/speeduino/corrections.h b/speeduino/corrections.h
index cd038dd1ce..df0275d57f 100644
--- a/speeduino/corrections.h
+++ b/speeduino/corrections.h
@@ -45,6 +45,5 @@ uint16_t correctionsDwell(uint16_t dwell);
 bool isFixedTimingOn(void);
 
 extern uint16_t AFRnextCycle;
-extern uint8_t aseTaper;
 
 #endif // CORRECTIONS_H
diff --git a/speeduino/globals.h b/speeduino/globals.h
index 10ddbbf05f..1b1f1fee1f 100644
--- a/speeduino/globals.h
+++ b/speeduino/globals.h
@@ -521,6 +521,7 @@ struct config2 {
   byte crkngAddCLTAdv : 1;
   byte includeAFR : 1; //< Enable AFR compensation ? (See also @ref config2.incorporateAFR)
   byte hardCutType : 1;
+  // cppcheck-suppress misra-c2012-6.1
   LoadSource ignAlgorithm : 3;
   byte indInjAng : 1;
   byte injOpen;     ///< Injector opening time (ms * 10)
@@ -533,6 +534,7 @@ struct config2 {
   byte nCylinders : 4; ///< Number of cylinders
 
   //config2 in ini
+  // cppcheck-suppress misra-c2012-6.1
   LoadSource fuelAlgorithm : 3;///< Fuel algorithm - 0=Manifold pressure/MAP (LOAD_SOURCE_MAP, default, proven), 1=Throttle/TPS (LOAD_SOURCE_TPS), 2=IMAP/EMAP (LOAD_SOURCE_IMAPEMAP)
   byte fixAngEnable : 1; ///< Whether fixed/locked timing is enabled (0=disable, 1=enable, See @ref configPage4.FixAng)
   byte nInjectors : 4;   ///< Number of injectors
@@ -1031,6 +1033,7 @@ struct config10 {
   byte knock_recoveryStep; //Byte 121
 
   //Byte 122
+  // cppcheck-suppress misra-c2012-6.1
   LoadSource fuel2Algorithm : 3;
   byte fuel2Mode : 3;
   byte fuel2SwitchVariable : 2;
@@ -1104,6 +1107,7 @@ struct config10 {
   byte fuelTempValues[6]; //180
 
   //Byte 186
+  // cppcheck-suppress misra-c2012-6.1
   LoadSource spark2Algorithm : 3;
   byte spark2Mode : 3;
   byte spark2SwitchVariable : 2;
diff --git a/speeduino/secondaryTables.cpp b/speeduino/secondaryTables.cpp
index 1ca29a7b39..2e917875f2 100644
--- a/speeduino/secondaryTables.cpp
+++ b/speeduino/secondaryTables.cpp
@@ -13,7 +13,7 @@
 static inline uint8_t getVE2(void)
 {
   currentStatus.fuelLoad2 = getLoad(configPage10.fuel2Algorithm, currentStatus);
-  return get3DTableValue(&fuelTable2, currentStatus.fuelLoad2, currentStatus.RPM); //Perform lookup into fuel map for RPM vs MAP value
+  return get3DTableValue(&fuelTable2, currentStatus.fuelLoad2, (table3d_axis_t)currentStatus.RPM); //Perform lookup into fuel map for RPM vs MAP value
 }
 
 static inline bool fuelModeCondSwitchRpmActive(void) {
@@ -59,8 +59,8 @@ void calculateSecondaryFuel(void)
     currentStatus.VE2 = getVE2();
     BIT_SET(currentStatus.status3, BIT_STATUS3_FUEL2_ACTIVE); //Set the bit indicating that the 2nd fuel table is in use. 
     //Fuel 2 table is treated as a % value. Table 1 and 2 are multiplied together and divided by 100
-    uint16_t combinedVE = percentage(currentStatus.VE2, (uint16_t)currentStatus.VE1);
-    currentStatus.VE = min(MAX_VE, combinedVE);
+    uint16_t combinedVE = div100((uint16_t)currentStatus.VE2 * (uint16_t)currentStatus.VE1);
+    currentStatus.VE = (uint8_t)min(MAX_VE, combinedVE);
   }
   else if(configPage10.fuel2Mode == FUEL2_MODE_ADD)
   {
@@ -68,7 +68,7 @@ void calculateSecondaryFuel(void)
     BIT_SET(currentStatus.status3, BIT_STATUS3_FUEL2_ACTIVE); //Set the bit indicating that the 2nd fuel table is in use. 
     //Fuel tables are added together, but a check is made to make sure this won't overflow the 8-bit VE value
     uint16_t combinedVE = (uint16_t)currentStatus.VE1 + (uint16_t)currentStatus.VE2;
-    currentStatus.VE = min(MAX_VE, combinedVE);
+    currentStatus.VE = (uint8_t)min(MAX_VE, combinedVE);
   }
   else if(fuelModeCondSwitchActive() || fuelModeInputSwitchActive())
   {
@@ -90,7 +90,7 @@ static constexpr int16_t MIN_ADVANCE = INT8_MIN; // out-of-line constant require
 
 static inline uint8_t lookupSpark2(void) {
   currentStatus.ignLoad2 = getLoad(configPage10.spark2Algorithm, currentStatus);
-  return get3DTableValue(&ignitionTable2, currentStatus.ignLoad2, currentStatus.RPM);  
+  return get3DTableValue(&ignitionTable2, currentStatus.ignLoad2, (table3d_axis_t)currentStatus.RPM);  
 }
 
 /**
@@ -100,9 +100,9 @@ static inline uint8_t lookupSpark2(void) {
  */
 static inline int8_t getAdvance2(void)
 {
-  int16_t advance2 = (int16_t)lookupSpark2() - INT16_C(OFFSET_IGNITION);
+  int16_t lookUpResult = (int16_t)lookupSpark2() - INT16_C(OFFSET_IGNITION);
   // Clamp to return type range.
-  advance2 = constrain(advance2, MIN_ADVANCE, MAX_ADVANCE);
+  int8_t advance2 = (int8_t)constrain(lookUpResult, MIN_ADVANCE, MAX_ADVANCE);
 #if !defined(UNIT_TEST)
   //Perform the corrections calculation on the secondary advance value, only if it uses a switched mode
   if( (configPage10.spark2SwitchVariable == SPARK2_MODE_CONDITIONAL_SWITCH) || (configPage10.spark2SwitchVariable == SPARK2_MODE_INPUT_SWITCH) ) { 
@@ -156,9 +156,9 @@ void calculateSecondarySpark(void)
       BIT_SET(currentStatus.status5, BIT_STATUS5_SPARK2_ACTIVE);
       uint8_t spark2Percent = lookupSpark2();
       //Spark 2 table is treated as a % value. Table 1 and 2 are multiplied together and divided by 100
-      int16_t combinedAdvance = div100((int16_t)((int16_t)spark2Percent * (int16_t)currentStatus.advance1));
+      int16_t combinedAdvance = div100((int16_t)spark2Percent * (int16_t)currentStatus.advance1);
       //make sure we don't overflow and accidentally set negative timing: currentStatus.advance can only hold a signed 8 bit value
-      currentStatus.advance = (int8_t)min((int16_t)MAX_ADVANCE, combinedAdvance);
+      currentStatus.advance = (int8_t)min(MAX_ADVANCE, combinedAdvance);
 
       // This is informational only, but the value needs corrected into the int8_t range
       currentStatus.advance2 = (int8_t)max(MIN_ADVANCE, (int16_t)((int16_t)spark2Percent-INT16_C(OFFSET_IGNITION)));
@@ -169,7 +169,7 @@ void calculateSecondarySpark(void)
       currentStatus.advance2 = getAdvance2();
       //Spark tables are added together, but a check is made to make sure this won't overflow the 8-bit VE value
       int16_t combinedAdvance = (int16_t)currentStatus.advance1 + (int16_t)currentStatus.advance2;
-      currentStatus.advance = min(MAX_ADVANCE, combinedAdvance);
+      currentStatus.advance = (int8_t)min(MAX_ADVANCE, combinedAdvance);
     }
     else if(sparkModeCondSwitchActive() || sparkModeInputSwitchActive())
     {
diff --git a/speeduino/statuses.h b/speeduino/statuses.h
index 2676249bba..8b49f9c945 100644
--- a/speeduino/statuses.h
+++ b/speeduino/statuses.h
@@ -87,14 +87,22 @@ using byte = uint8_t;
 * unit based values in similar variable(s) without ADC part in name (see sensors.ino for reading of sensors).
 */
 struct statuses {
+  // cppcheck-suppress misra-c2012-6.1 ; False positive - MISRA C:2012 Rule (R 6.1) permits the use of boolean for bit fields.
   volatile bool hasSync : 1; /**< Flag for crank/cam position being known by decoders (See decoders.ino).
   This is used for sanity checking e.g. before logging tooth history or reading some sensors and computing readings. */
+  // cppcheck-suppress misra-c2012-6.1
   bool initialisationComplete : 1; //Tracks whether the setup() function has run completely
+  // cppcheck-suppress misra-c2012-6.1
   bool clutchTrigger : 1;
+  // cppcheck-suppress misra-c2012-6.1
   bool previousClutchTrigger : 1;
+  // cppcheck-suppress misra-c2012-6.1
   volatile bool fpPrimed : 1; //Tracks whether or not the fuel pump priming has been completed yet
+  // cppcheck-suppress misra-c2012-6.1
   volatile bool injPrimed : 1; //Tracks whether or not the injector priming has been completed yet
+  // cppcheck-suppress misra-c2012-6.1
   volatile bool tachoSweepEnabled : 1;
+  // cppcheck-suppress misra-c2012-6.1
   volatile bool tachoAlt : 1;
     
   uint16_t RPM;   ///< RPM - Current Revs per minute