Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System (2GR-FKS) - Diagnostic Codes (5 Of 6) >> SFI System >> DTC P0597-12: Thermostat Heater Control Circuit Short to Battery [12/2019 - 10/2022] >> Typical Malfunction Thresholds