Troubleshooting

DTC P0115 - Engine Coolant Temp. Circuit Malfunction

CIRCUIT DESCRIPTION
A thermistor built into the engine coolant temperature sensor changes the resistance value according to the engine coolant temperature.
The structure of the sensor and connection to the ECM is the same as in the intake air temp. circuit.
If the ECM detects the DTC P0115, it operates the fail safe function in which the engine coolant temp. is assumed to be 80°C (176°F).








DETECTING CONDITION AND TROUBLE AREA

HINT: After confirming DTC P0115 use the OBD II scan tool or TOYOTA hand-held tester to confirm the engine coolant temperature from "CURRENT DATA".





WIRING DIAGRAM

















INSPECTION PROCEDURE

HINT: If DTC "P0110" (intake air temp. circuit malfunction), "P0115" (engine coolant temp. circuit malfunction), "P0120" (throttle/pedal position sensor/switch "A" circuit malfunction) are output simultaneously, E2 (sensor ground) may be open.