DSD Information System
Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 87 (Engine Control System (A25A-FXS) - Diagnostic Codes (P0520-P05A2)) >> SFI System >> DTC P0597-14: Thermostat Heater Control Circuit Short to Ground or Open [12/2019 - 10/2021] >> Monitor Description

Monitor Description

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The ECM monitors the output voltage while the thermostat heater is operating.

The thermostat heater turns on and off according to ON/OFF switching of a transistor inside the ECM.

If a continuous mismatch occurs between the ECM transistor state and the output voltage, the ECM determines there is a malfunction in the thermostat heater circuit and stores a DTC.

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