1Nz-Fe Engine Control. Dtc P0115 Engine Coolant Temperature Circuit Malfunction

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 the same as those of the intake air temperature sensor.

HINT:

When any of DTCs P0115, P0117 and P0118 is stored, 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.

DTC No.	DTC Detection Condition	Trouble Area
P0115	An open or short in the engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic).	Open or short in engine coolant temperature sensor circuit Engine coolant temperature sensor ECM
P0117	A short in the engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic).	Short in engine coolant temperature sensor circuit Engine coolant temperature sensor ECM
P0118	An open in the engine coolant temperature sensor circuit for 0.5 seconds (1 trip detection logic).	Open in engine coolant temperature sensor circuit Engine coolant temperature sensor ECM

HINT:

When any of these DTCs are output, check the engine coolant temperature using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

Temperature Displayed	Malfunction
-40°C (-40°F)	Open circuit
Higher than 135°C (275°F)	Short circuit

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 in 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 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 stores 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 stores 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 stores DTC P0117.
If the malfunction is not repaired successfully, a DTC is stored 0.5 seconds after the engine is next started.

MONITOR STRATEGY

Related DTCs	P0115: Engine Coolant Temperature Sensor Range Check (Fluctuating) P0117: Engine Coolant Temperature Sensor Range Check (Low Voltage) P0118: Engine Coolant Temperature Sensor Range Check (High Voltage)
Required Sensors/Components (Main)	Engine coolant temperature sensor
Required Sensors/Components (Related)	-
Frequency of Operation	Continuous
Duration	0.5 seconds
MIL Operation	Immediate
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever following DTCs not present

None

TYPICAL MALFUNCTION THRESHOLDS

P0115
Engine coolant temperature sensor voltage	Less than 0.14 V, or higher than 4.91 V [Higher than 135°C (275°F), or below -60°C (-76°F)]

P0117
Engine coolant temperature sensor voltage [Engine coolant temperature]	Less than 0.14 V [Higher than 135°C (275°F)]

P0118
Engine coolant temperature sensor voltage [Engine coolant temperature]	More than 4.91 V [Below -60°C (-76°F)]

COMPONENT OPERATING RANGE

Engine coolant temperature sensor voltage [Engine coolant temperature]

0.14 to 4.91 V [-60 to 135°C (-76 to 275°F)]

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON and turn the Techstream on.
Wait 0.5 seconds or more.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Read pending DTCs.
HINT:
1. If a pending DTC is output, the system is malfunctioning.
2. If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0115, P0117 or P0118.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.

If the judgment result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (YARIS_NCP93 RM000000PDK0T5X.html).
HINT:
1. If a permanent DTC is output, the system is malfunctioning.
2. If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Yaris. Ncp93, 131.1Nz-Fe Engine Control.Sfi System (For Sedan).
Dtc
P0115 Engine Coolant Temperature Circuit Malfunction

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 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.
If DTC P0117 is stored, check that the engine does not overheat (the DTC P0117 may be stored due to engine overheating).

1.READ VALUE USING TECHSTREAM (ENGINE COOLANT TEMPERATURE)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

Read the value displayed on the Techstream.
Standard value:
Between 75 and 100°C (167 and 212°F) with warm engine.
Result
Result
Proceed to
-40°C (-40°F)
A
Higher than 135°C (275°F)
B
Between 75 and 100°C (167 and 212°F)
C
HINT:
1. If there is an open circuit, the Techstream indicates -40°C (-40°F).
2. If there is a short circuit, the Techstream indicates higher than 135°C (275°F).

Result
Result	Proceed to
-40°C (-40°F)	A
Higher than 135°C (275°F)	B
Between 75 and 100°C (167 and 212°F)	C

Go to step 4

CHECK FOR INTERMITTENT PROBLEMS (YARIS_NCP93 RM000000PDQ0Q2X.html)

A

2.READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN WIRE HARNESS)

Disconnect the engine coolant temperature sensor connector.

Connect terminals 1 and 2 of the engine coolant temperature sensor connector on the wire harness side.

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

Read the value displayed on the Techstream.
Standard value:
Higher than 135°C (275°F)
Text in Illustration
*1
Engine Coolant Temperature Sensor
*2
ECM
*a
Front view of wire harness connector
(to Engine Coolant Temperature Sensor)
HINT:
Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (YARIS_NCP93 RM000004NJD006X.html).

Text in Illustration
*1	Engine Coolant Temperature Sensor
*2	ECM
*a	Front view of wire harness connector (to Engine Coolant Temperature Sensor)

Go to step 3

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (YARIS_NCP93 RM000003VID00IX.html)

3.CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

Disconnect the engine coolant temperature sensor connector.

Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection
Condition
Specified Condition
C55-2 - C51-93 (THW)
Always
Below 1 Ω
C55-1 - C51-94 (ETHW)
Always
Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE ECM (YARIS_NCP93 RM000001CN002IX.html)

4.READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS)

Disconnect the engine coolant temperature sensor connector.

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

Read the value displayed on the Techstream.
Standard value:
-40°C (-40°F)
Text in Illustration
*1
Engine Coolant Temperature Sensor
*2
ECM
HINT:
Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (YARIS_NCP93 RM000004NJD006X.html).

Text in Illustration
*1	Engine Coolant Temperature Sensor
*2	ECM

Go to step 5

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (YARIS_NCP93 RM000003VID00IX.html)

5.CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

Disconnect the engine coolant temperature sensor connector.

Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection
Condition
Specified Condition
C55-2 or C51-93 (THW) - Body ground
Always
10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE ECM (YARIS_NCP93 RM000001CN002IX.html)

Tester Connection	Condition	Specified Condition
C55-2 - C51-93 (THW)	Always	Below 1 Ω
C55-1 - C51-94 (ETHW)	Always	Below 1 Ω