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Home >> Infiniti >> 2008 >> G35 x >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS U1000 Through P0153 >> DTC P0128: Thermostat Function >> DTC Logic >> DTC Detection Logic
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DTC Detection 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 leak in the seal or the thermostat stuck open.

DTC DETECTING CONDITION CHART

DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0128 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