P0117

2AZ-FE ENGINE CONTROL: SFI SYSTEM: P0115,P0117,P0118: 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, whose resistance value varies according to the engine coolant temperature, is built into the engine coolant temperature sensor.
The structure of the sensor and its connection to the ECM are similar to that of 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: 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 becomes low, the resistance in the thermistor increases. When the temperature becomes high, the resistance drops. These 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 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 circuit and sets a DTC.
Example:
If the sensor output voltage is more than 4.91 V 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 less than 0.14 V 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: Read freeze frame data using the Techstream. The ECM 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 USING TECHSTREAM (ENGINE COOLANT TEMPERATURE)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(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 Value:
Between 80°C and 100°C (167°F and 212°F) with a 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).

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 ignition switch to ON.
(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 Value:
140°C (284°F).
(h) Reconnect the engine coolant temperature sensor connector.
NG -- CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)
OK -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
3. CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

(a) Disconnect the engine coolant temperature sensor connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:

(d) Reconnect the engine coolant temperature sensor connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)
OK -- REPLACE ECM
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 ignition switch to ON.
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
(f) Read the value displayed on the Techstream.
Standard Value:
-40°C (-40°F)
(g) Reconnect the engine coolant temperature sensor connector.
NG -- CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)
OK -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
5. CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

(a) Disconnect the engine coolant temperature sensor connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance: