P0118
3MZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0115: Engine Coolant Temperature Circuit Malfunction
DTC P0115 - Engine Coolant Temperature Circuit Malfunction
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 sensor, of which the resistance value varies according to the engine coolant temperature.
The structure of the sensor and its connection to the ECM (included in the hybrid vehicle control ECU) are similar to the intake air temperature sensor.
HINT: When any of DTCs P0115, P0117 and P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the engine coolant temperature is estimated to be 80°C (176°F) by the ECM. Fail-safe mode continues until a pass condition is detected.
HINT: When any of these DTCs are set, check the engine coolant temperature by entering the following menus on the Techstream: Powertrain / Engine and ECT / Data List / Coolant Temp.
MONITOR DESCRIPTION
The engine coolant temperature sensor is used to monitor the engine coolant temperature. The engine coolant temperature sensor has a thermistor with a resistance that varies according to the temperature of the engine coolant. When the coolant temperature is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are reflected in the output voltage from the sensor. The ECM (included in the hybrid vehicle control ECU) monitors the sensor voltage and uses this value to calculate the engine coolant temperature. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the engine coolant temperature sensor and sets a DTC.
Example:
If the sensor output voltage is -40°C (-40°F) for 0.5 seconds or more, the ECM determines that there is an open in the engine coolant temperature sensor circuit, and sets DTC P0118. Conversely, if the voltage output is more than 140°C (284°F) for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets DTC P0117.
If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started.
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 B11 as the ground terminal are output simultaneously, terminal B11 may have an open circuit.
- Read freeze frame data using the Techstream. The ECM (included in the hybrid vehicle control ECU) records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
PROCEDURE
1. READ VALUE OF TECHSTREAM (ENGINE COOLANT TEMPERATURE)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
(e) Read the value displayed on the Techstream.
Standard:
Between 80°C and 97°C (176°F and 207°F) with warm engine.
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 higher.
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 engine coolant temperature sensor connector.
(b) Connect terminals 1 and 2 of the engine coolant temperature sensor connector on the wire harness side.
(c) Connect the Techstream to the DLC3.
(d) Turn the power switch on (IG).
(e) Turn the Techstream on.
(f) Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
(g) Read the value displayed on the Techstream.
Standard:
140°C (284°F) or higher.
(h) Reconnect the engine coolant temperature sensor connector.
NG -- CHECK HARNESS AND CONNECTOR (CHECK FOR OPEN IN HYBRID VEHICLE CONTROL ECU)
OK -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
3. CHECK HARNESS AND CONNECTOR (CHECK FOR OPEN IN HYBRID VEHICLE CONTROL ECU)
(a) Disconnect the engine coolant temperature sensor connector.
(b) Connect terminal THW of the hybrid vehicle control ECU connector.
HINT: Before checking, do visual and contact pressure checks on the hybrid vehicle control ECU sensor connector.
(c) Connect the Techstream to the DLC3.
(d) Turn the power switch on (IG).
(e) Turn the Techstream on.
(f) Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
(g) Read the value displayed on the Techstream.
Standard:
140°C (284°F) or higher.
(h) Reconnect the engine coolant temperature sensor connector.
NG -- REPLACE HYBRID VEHICLE CONTROL ECU
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - HYBRID VEHICLE CONTROL ECU)
4. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)
(a) Disconnect the engine coolant temperature sensor connector.
(b) Connect the Techstream to the DLC3.
(c) Turn the power switch on (IG).
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
(f) Read the value displayed on the Techstream.
Standard:
-40°C (-40°F)
(g) Reconnect the engine coolant temperature sensor connector.
NG -- READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN HYBRID VEHICLE CONTROL ECU)
OK -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
5. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN HYBRID VEHICLE CONTROL ECU)
(a) Disconnect the hybrid vehicle control ECU connectors.
(b) Connect the Techstream to the DLC3.
(c) Turn the power switch on (IG).
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
(f) Read the value displayed on the Techstream.
Standard:
-40°C (-40°F)
(g) Reconnect the hybrid vehicle control ECU connector.
NG -- REPLACE HYBRID VEHICLE CONTROL ECU
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR