P0118

3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0115: Engine Coolant Temperature Circuit

DTC P0115 - Engine Coolant Temperature Circuit

DTC P0117 - Engine Coolant Temperature Circuit Low Input

DTC P0118 - Engine Coolant Temperature Circuit High Input

DESCRIPTION





A thermistor is built into the Engine Coolant Temperature (ECT) sensor and changes the resistance value according to the engine coolant temperature.
The structure of the sensor and connection to the ECM is the same as the Intake Air Temperature (IAT) sensor.
HINT: If the ECM detects the DTC P0115, P0117 or P0118, it operates the fail-safe function in which the ECT is assumed to be 80°C (176°F).





HINT: Confirm the ECT using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.





MONITOR DESCRIPTION

The ECT sensor is used to monitor the engine coolant temperature. The ECT sensor has a thermistor that varies its resistance according to the temperature of the engine coolant. When the coolant temperature is low, the resistance in the thermistor increases. When the temperature is high, the resistance drops. The variations in resistance are reflected in the output voltage from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the ECT. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the ECT sensor and sets a DTC.
Example:
When the ECM calculates that the ECT is -40°C (-40°F) (P0118) or more than 140°C (284°F) (P0117) and that either condition continues for 0.5 seconds or more, the ECM will set a DTC.
This monitor runs for 0.5 seconds after the ignition switch is turned ON.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

P0115:





P0117:





P0118:





COMPONENT OPERATING RANGE





WIRING DIAGRAM





INSPECTION PROCEDURE
HINT:
- If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
- Read freeze frame data using the Techstream. Freeze frame data records the engine conditions when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was LEAN or RICH, and other data from the time the malfunction occurred.

PROCEDURE

1. READ VALUE USING TECHSTREAM (ENGINE COOLANT TEMPERATURE)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON and turn the tester ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Coolant Temp.
(d) Read the values.
OK:
Same value as the actual ECT
Result:





HINT: If there is an open circuit, the Techstream indicates -40°C (-40°F).
If there is a short circuit, the Techstream indicates 140°C (284°F) or more.

C -- CHECK FOR INTERMITTENT PROBLEMS
B -- READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)
A -- Continue to next step.
2. READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN WIRE HARNESS)




(a) Disconnect the E7 ECT sensor connector.
(b) Connect terminals 1 and 2 of the ECT sensor wire harness side connector.
(c) Turn the ignition switch ON.
(d) Read the value.
OK:
Temperature value is 140°C (284°F) or more
OK -- CONFIRM GOOD CONNECTION AT SENSOR. IF OK, REPLACE ENGINE COOLANT TEMPERATURE SENSOR
NG -- Continue to next step.
3. READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN ECM)




(a) Disconnect the E7 ECT sensor connector.
(b) Connect terminal THW of the E4 ECM connector and terminal E2 of the E2 ECM connector.
HINT: Before checking, do a visual and contact pressure check for the ECM connector.
(c) Turn the ignition switch ON.
(d) Read the value.
OK:
Temperature value is 140°C (284°F) or more
NG -- CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR
4. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)




(a) Disconnect the E7 ECT sensor connector.
(b) Turn the ignition switch ON.
(c) Read the value.
OK:
Temperature value is -40°C (-40°F)
OK -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
NG -- Continue to next step.
5. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)




(a) Disconnect the E7 ECT sensor connector.
(b) Disconnect the E2 and E4 ECM connectors.
(c) Turn the ignition switch ON.
(d) Read the value.
OK:
Temperature value is -40°C (-40°F)
NG -- REPLACE ECM
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR