2Zr-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 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.

DTC No.	DTC Detection Condition	Trouble Area
P0115	Open or short in 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	Short in 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	Open in 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 set, check the engine coolant temperature by entering 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 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.

MONITOR STRATEGY

Related DTCs	P0115: Engine coolant temperature sensor range check (Chattering) 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 [Engine coolant temperature]	Less than 0.14 V, or more than 4.91 V [More than 135°C (275°F), or less than -60°C (-76°F)]

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

P0118
Engine coolant temperature sensor voltage [Engine coolant temperature]	More than 4.91 V [Less than -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 the DTCs (even if no DTCs are stored, perform the clear DTC operation) (COROLLA_ZRE142 RM000000PDK0ZAX.html).
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 the 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 (COROLLA_ZRE142 RM000000PDK0ZAX.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

Corolla. Zre142 Aze141.2Zr-Fe Engine Control.Sfi System.
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 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.
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°C and 100°C (167°F and 212°F) with warm engine.

Result:

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

Go to step 4

CHECK FOR INTERMITTENT PROBLEMS (COROLLA_ZRE142 RM000000PDQ0VMX.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).

Reconnect the engine coolant temperature sensor connector.

Go to step 3

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (COROLLA_ZRE142 RM0000030LG014X.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
B58-2 - B31-64 (THW)
Always
Below 1 Ω
B58-1 - B31-65 (ETHW)
Always
Below 1 Ω

Reconnect the engine coolant temperature sensor connector.

Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

REPLACE ECM (COROLLA_ZRE142 RM000001CN0030X.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)

Reconnect the engine coolant temperature sensor connector.

Go to step 5

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (COROLLA_ZRE142 RM0000030LG014X.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
B58-2 or B31-64 (THW) - Body ground
Always
10 kΩ or higher

Reconnect the engine coolant temperature sensor connector.

Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR - ECM)

REPLACE ECM (COROLLA_ZRE142 RM000001CN0030X.html)

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

Tester Connection	Condition	Specified Condition
B58-2 - B31-64 (THW)	Always	Below 1 Ω
B58-1 - B31-65 (ETHW)	Always	Below 1 Ω