Toyota 1 MZ–FE Manual page 457

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 coolant temperature.
The structure of the sensor and connection to the ECM is the same as in the intake air temp. circuit
malfunction shown on page EG2–451.
If the ECM records the diagnostic trouble code P01 15, it operates the fail safe function, keeping the engine
coolant temp. at a constant 80
Diagnostic Trouble Code Detecting Condition
DTC No.
Open or short in engine coolant temp. sensor
P0115
circuit.
HINT: After confirming DTC P01 15 use the OBDll scan tool or TOYOTA hand–held tester to confirm the
engine coolant temperature from "CURRENT DATA".
Temperature Displayed Malfunction
WIRING DIAGRAM
1MZ–FE ENGINE
2 2
C (176 F).
– 402C (– 402F)
1202C (2482F) or more
– CIRCUIT INSPECTION
Trouble Area
Open or short in engine coolant temp. sensor
circuit.
Engine coolant temp. sensor.
ECM
Open circuit
Short circuit
EG2–457