Diagnosis & Repair
- Using Toyota hand-held tester or scan tool, check for any other DTCs. If only DTC P0116 exists, go to next step. If other DTCs exist, diagnose and repair those DTCs first and retest.
- Remove and inspect cooling system thermostat for damage and proper operation. Thermostat is located behind thermostat housing which is located just behind the generator. If thermostat is defective, replace thermostat. If thermostat is okay, replace ECT sensor. ECT sensor is located on coolant housing at flywheel end of cylinder head and contains Green 2-pin electrical connector with White and Brown wires.