Troubleshooting
DTC P0115 ENGINE COOLANT TEMPERATURE CIRCUIT MALFUNCTIONCIRCUIT DESCRIPTION
Detection Item:
A thermistor built into the engine coolant temp. sensor changes the resistance value according to the engine coolant temp.
The structure of the sensor and connection to the ECM is the same as in the intake air temperature circuit malfunction.
If the ECM detects the DTC P0115, it operates fail safe function in which the engine coolant temperature is assumed to be 80 °C (176 °F).
HINT: After confirming DTC P0115, use the OBD II scan tool or TOYOTA hand-held tester to confirm the engine coolant temp. from "CURRENT DATA".
Wiring Diagram:
Step 1 - 2:
Step 3 - 4:
Step 5:
INSPECTION PROCEDURE
HINT:
- If DTC P0110, P0115 and P0120 are output simultaneously, E2 (sensor ground) may be open.
- Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame 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 warmed up or not, the air-fuel ratio 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 check mode, 1 trip detection logic is possible instead of 2 trip detection logic and sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.
1. Clear the DTC (See step 3).
2. Set the check mode (See step 3).
3. Perform a simulation test.
4. Check the connector and terminal.
5. Handle the connector.