Detection Condition

DTC P1432 indicates voltage of Thermostat Heater Control (THTRC) circuit went below a calibrated limit for a calibrated amount of time. The system consists of a high temperature thermostat that has a resistive heater within a wax element. The heater is controlled by the PCM and dependent on engine speed, throttle position, engine load, vehicle speed, air charge temperature, transmission oil temperature, and engine coolant temperature. During high speed, high load, and high temperature conditions (air charge, transmission oil or engine coolant), PCM output is energized with a duty cycle to thermostat heater. This heats the wax and forces the thermostat to rapidly open wider allowing extra coolant to flow from radiator. This will reduce engine coolant temperature and improve performance demand.