Troubleshooting
DTC P0118 Coolant Temperature Circuit High InputCIRCUIT DESCRIPTION
DTC Detection Condition:
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 DTC P0110.
If the ECM detects the DTC P0115, DTC P0117 or DTC P0118 it operates the fail-safe functions 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 hand-held tester to confirm the engine coolant temperature from the CURRENT DATA.
Wiring Diagram:
Step 1:
Step 2 - 3:
Step 4 - 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 hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when a 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.
CHECK FOR INTERMITTENT PROBLEMS
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 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. Check the connector connection.