Diagnosis & Repair
WARNING: This page is about a different car, the 2002 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
- 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 on driver's side front of engine, just behind cooling fan. If thermostat is defective, replace thermostat. If thermostat is okay, replace ECT sensor. ECT sensor is located behind upper timing belt cover, on top of intake manifold and contains Dark Gray 2-pin electrical connector with Green/Yellow and Brown/Black wires. See ENGINE COOLANT TEMPERATURE SENSOR under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.