Troubleshooting

DTC P0115 ENGINE COOLANT TEMPERATURE CIRCUIT MALFUNCTION


CIRCUIT DESCRIPTION

Detection Item:

A thermistor built in the engine coolant temperature sensor changes the resistance value by to the engine coolant temperature.

The structure of the sensor and connection to the ECM is the same as one in the intake air temperature circuit malfunction.

If the ECM detects the DTC P0115, it operates the fail-safe function in which the engine coolant temperature is assumed to be 80 °C (176 °C).






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

Wiring Diagram:

Steps 1 - 2:

Steps 3 - 4:

Step 5:

INSPECTION PROCEDURE

HINT:
- If DTCs P0110, P0115, P0120 and P1410 are output simultaneously, E2 (sensor ground) may be open.
- Read freeze frame data using LEXUS hand-held tester or OBD II scan tool, as freeze frame data records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich etc. at the time of the malfunction.