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Home >> Mazda >> 2021 >> 3 Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Symptom Troubleshooting - Engine (VINS 7, L, M) >> Cooling System Concerns-Overheating >> Notes

Cooling System Concerns-Overheating: Notes

COOLING SYSTEM CONCERNS-OVERHEATING (VINs 7, L, M) (US) DESCRIPTION AND POSSIBLE CAUSE

Troubleshooting item Cooling system concerns-overheating
Description
  • The engine coolant temperature is abnormally high.
Possible cause
  • Engine heat generation amount is excessive
    • Engine speed is high and remains high for continuous long periods
  • PCM DTC is stored
  • Improper operation of A/C system
  • Insufficient air blow volume
  • Cooling fan inoperative
  • Active air shutter is fully-closed and does not operate (With active air shutter)
  • Fan rotation speed decreases (such as generator malfunction) due to battery voltage decrease
  • ECT sensor No. 1 malfunction (value lower than actual engine coolant temperature detected)
  • ECT sensor No. 2 malfunction (value lower than actual engine coolant temperature detected)
  • Cooling system cap malfunction
  • Cooling fan motor assembly malfunction
  • Cooling fan motor connector malfunction
  • Active air shutter malfunction (With active air shutter)
  • Improper indication of high engine coolant temperature warning indication
  • ECT sensor No. 1 signal malfunction
  • ECT sensor No. 2 signal malfunction
  • Center display malfunction
  • Body control module (BCM) malfunction
  • Multi-information display malfunction
  • Blown fuse
  • Engine coolant system malfunction
  • Improper engine coolant level
  • Water pump malfunction
  • Engine coolant performance deterioration
  • Coolant leakage (engine internal, external)
  • Improper water/anti-freeze mixture
  • Thermostat malfunction (not fully open) (built-into coolant control valve)
  • Radiator malfunction (clogging)
  • Inappropriate engine coolant concentration (engine coolant in radiator freezes and engine coolant does not flow)
  • Foreign matter penetration in engine coolant
  • Leakage around heater unit in passenger compartment
  • Drive belt damage
System wiring diagram
  • Not applicable
Connector diagram
  • Not applicable