DTC P0128 - Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)

2018 Ford Fusion Platinum HybridSECTION DTC P0128 - Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
P0128 - COOLANT THERMOSTAT (COOLANT TEMPERATURE BELOW THERMOSTAT REGULATING TEMPERATURE)

Description:  This DTC sets when the thermostat monitor has not achieved the required engine operating temperature within a specified amount of time after starting the engine.
Possible Causes: 
  • Insufficient warm up time
  • Low engine coolant level
  • Leaking or stuck open thermostat
  • Cylinder head temperature (CHT) sensor concern
Diagnostic Aids:  Refer to ENHANCED THERMOSTAT MONITOR for system information.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to PINPOINT TEST DL .
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.