Home >> Subaru >> 2004 >> Forester XT, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> Testing & Diagnosis >> Engine (Diagnostics) (H4DOTC) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature) >> DTC Detecting Condition: