Toyota Fortuner. Dtc P0115/22 Engine Coolant Temperature Circuit

A thermistor is built into the Engine Coolant Temperature (ECT) sensor and changes its resistance value according to the engine coolant temperature.
The structure of the sensor and its connection to the ECM is the same as that of the intake air temperature sensor and its connection.

HINT:

If the ECM detects DTC P0115/22, P0117/22 or P0118/22, the ECM enters fail-safe mode in which the ECT is assumed to be 80°C (176°F).

DTC No.	DTC Detection Condition	Trouble Area
P0115/22	Open or short in ECT sensor circuit for 0.5 seconds	Open or short in ECT sensor circuit ECT sensor ECM
P0117/22	Short in ECT sensor circuit for 0.5 seconds	Short in ECT sensor circuit ECT sensor ECM
P0118/22	Open in ECT sensor circuit for 0.5 seconds	Open in ECT sensor circuit ECT sensor ECM

HINT:

When DTC P0115/22, P0117/22 or P0118/22 is detected, check the engine coolant temperature by entering the following menus on the intelligent tester: Powertrain / Engine and ECT / Data List / Coolant Temp.

Temperature Displayed	Malfunction
-40°C (-40°F)	Open circuit
140°C (284°F) or more	Short circuit

MONITOR DESCRIPTION

The ECT sensor is used to monitor the engine coolant temperature. The ECT sensor has a thermistor that varies its resistance depending on 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 voltage output 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) (P0118/22) or more than 140°C (284°F) (P0117/22) 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 (1 trip detection logic).

WIRING DIAGRAM

Toyota Fortuner. Ggn50, 60 Kun51, 61 Tgn51 Lan50.2Tr-Fe Engine Control System.Sfi System.
Dtc
P0115/22 Engine Coolant Temperature Circuit

INSPECTION PROCEDURE

HINT:

If DTCs related 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 intelligent tester. 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.

When using intelligent tester:

1.READ OUTPUT DTC

Connect the intelligent tester to the DLC3.

Turn the ignition switch ON and turn the intelligent tester ON.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Read DTCs.
Result:
Display (DTC Output)
Proceed to
P0115/22
A
P0117/22
B
P0118/22
C

Go to step 5

Go to step 3

A

2.READ DATA LIST (ENGINE COOLANT TEMPERATURE)

Connect the intelligent tester to the DLC3.

Turn the ignition switch ON and turn the intelligent tester ON.

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

Read the value.
OK:
Temperature value is 80 to 97°C (176 to 207°F) after warming up the engine.
Result:
Temperature Displayed
Proceed to
-40°C (-40°F)
A
140°C (284°F) or more
B
OK (same as the actual engine coolant temperature)
C
HINT:
1. If there is an open circuit, the intelligent tester indicates -40°C (-40°F).
2. If there is a short circuit, the intelligent tester indicates 140°C (284°F) or more.

Go to step 5

CHECK FOR INTERMITTENT PROBLEMS

A

3.READ DATA LIST (CHECK FOR OPEN IN WIRE HARNESS)

Disconnect the W1 ECT sensor connector.

Connect terminals 1 and 2 of the W1 ECT sensor wire harness side connector.

Turn the ignition switch ON and turn the intelligent tester ON.

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

Read the value.
OK:
Temperature value is 140°C (284°F) or more

CONFIRM GOOD CONNECTION AT SENSOR. IF OK, REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG

4.READ DATA LIST (CHECK FOR OPEN IN ECM)

Disconnect the W1 ECT sensor connector.

Connect terminals THW and E2 of the E11 ECM connector.
HINT:
Before checking, perform a visual and contact pressure check on the ECM connector.

Turn the ignition switch ON and turn the intelligent tester ON.

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

Read the value.
OK:
Temperature value is 140°C (284°F) or more

REPAIR OR REPLACE HARNESS OR CONNECTOR

CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM

5.READ DATA LIST (CHECK FOR SHORT IN WIRE HARNESS)

Disconnect the W1 ECT sensor connector.

Turn the ignition switch ON and turn the intelligent tester ON.

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

Read the value.
OK:
Temperature value is -40°C (-40°F)

REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG

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

Disconnect the E11 ECM connector.

Disconnect the W1 ECT sensor connector.

Measure the resistance of the wire harness side connectors.
Standard resistance:
Tester Connection
Specified Condition
E11-32 (THW) - W1-2
Below 1 Ω
E11-28 (E2) - W1-1
Below 1 Ω
E11-32 (THW) or W1-2 - Body ground
10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE ECM

When not using intelligent tester:

1.CHECK ECM (THW VOLTAGE)

Turn the ignition switch ON.

Measure the voltage between terminals THW and E2 of the ECM connector.
Standard voltage:
Engine Coolant Temperature
Specified Condition
20°C (68°F)
0.5 to 3.4 V
80°C (176°F)
0.2 to 1.0 V

CHECK FOR INTERMITTENT PROBLEMS

NG

2.INSPECT ENGINE COOLANT TEMPERATURE SENSOR

Inspect the ECT sensor (Toyota Fortuner RM000000VW800FX_01_0001.html).

REPLACE ENGINE COOLANT TEMPERATURE SENSOR

OK

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

Disconnect the E11 ECM connector.

Disconnect the W1 ECT sensor connector.

Measure the resistance of the wire harness side connectors.
Standard resistance:
Tester Connection
Specified Condition
E11-32 (THW) - W1-2
Below 1 Ω
E11-28 (E2) - W1-1
Below 1 Ω
E11-32 (THW) or W1-2 - Body ground
10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE ECM

Temperature Displayed	Proceed to
-40°C (-40°F)	A
140°C (284°F) or more	B
OK (same as the actual engine coolant temperature)	C

Tester Connection	Specified Condition
E11-32 (THW) - W1-2	Below 1 Ω
E11-28 (E2) - W1-1	Below 1 Ω
E11-32 (THW) or W1-2 - Body ground	10 kΩ or higher

Engine Coolant Temperature	Specified Condition
20°C (68°F)	0.5 to 3.4 V
80°C (176°F)	0.2 to 1.0 V