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Home >> Infiniti >> 2012 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS U0101 To P0153 >> DTC P0128: Thermostat Function >> DTC Logic >> DTC Detection Logic
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DTC Detection Logic

NOTE: If DTC P0128 is displayed with DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308, first perform the trouble diagnosis for DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308. Refer to "DTC LOGIC ".

Engine coolant temperature has not risen enough to open the thermostat even though the engine has run long enough.

This is due to a leakage in the seal or the thermostat being stuck open.

DTC No. Trouble diagnosis name (Trouble diagnosis content) DTC detecting condition Possible cause
P0128 THERMOSTAT FUNCTION (Thermostat function) The engine coolant temperature does not reach to specified temperature even though the engine has run long enough.
  • Thermostat
  • Leakage from sealing portion of thermostat
  • Engine coolant temperature sensor