Troubleshooting

DTC P0115 Engine Coolant Temp. Circuit Malfunction

CIRCUIT DESCRIPTION

DTC Detection Condition:

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






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

Wiring Diagram:

Step 1 - 2:

Step 3 - 4:

Step 5:

INSPECTION PROCEDURE

HINT:
- If different DTCs that are related to different systems are output simultaneously while terminal E2 is used as a ground terminal, terminal E2 may be open.
- Read freeze frame data using the hand-held tester or the OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, this 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.

Check For Intermittent Problems

TOYOTA hand-held tester only:
By putting the vehicle's ECM in the check mode, 1 trip detection logic is possible instead of 2 trip detection logic and the sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.

1. Clear the DTCs.
2. Set the check mode.
3. Perform a simulation test.
4. Check the connector and terminal.
5. Handle the connector.