Dtc P0115 Engine Coolant Temperature Circuit


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING GTS (ENGINE COOLANT TEMPERATURE)

CHECK HARNESS AND CONNECTOR (CHECK FOR OPEN)

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

CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT)

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

DTC P0115 Engine Coolant Temperature Circuit


DESCRIPTION

The engine coolant temperature sensor senses the coolant temperature. A thermistor built into the sensor changes the resistance value according to the coolant temperature. The lower the coolant temperature, the greater the thermistor resistance value, and the higher the coolant temperature, the lower the thermistor resistance value (See Fig. 1).
The engine coolant temperature sensor is connected to the ECM. The 5 V power source voltage in the ECM is applied to the engine coolant temperature sensor from the terminal THW via a resistor R. That is, the resistor R and the engine coolant temperature sensor are connected in series. When the resistance value of the engine coolant temperature sensor changes in accordance with changes in the coolant temperature, the potential at the terminal THW also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability during cold engine operation.
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.5L-E Engine Control.Ecd System. Dtc P0115 Engine Coolant Temperature Circuit

DTC No.
DTC Detection Condition
Trouble Area
P0115
Open or short in engine coolant temperature sensor circuit for 0.5 seconds or more.
  1. Open or short in engine coolant temperature sensor circuit
  2. Engine coolant temperature sensor
  3. ECM

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.5L-E Engine Control.Ecd System. Dtc P0115 Engine Coolant Temperature Circuit


INSPECTION PROCEDURE

HINT:
Read freeze frame data using the GTS. Freeze frame data records the engine condition 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, and other data from the time the malfunction occurred.
1.READ VALUE USING GTS (ENGINE COOLANT TEMPERATURE)

  1. Connect the GTS to the DLC3.

  1. Turn the ignition switch to ON and turn the GTS on.

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

  1. Read the value.

    Result:

    Display
    		Proceed
    -40°C (-40°F)
    		A
    140°C (284°F) or more
    		B
    The same as actual engine coolant temperature
    		C
    HINT:
    1. If there is an open circuit, the GTS indicates -40°C (- 40°F).
    2. If there is a short circuit, the GTS indicates 140°C (284°F) or more.


B
Go to step 4

C
CHECK FOR INTERMITTENT PROBLEMS (LandCruiser RM000000VQG00VX.html)
A


2.CHECK HARNESS AND CONNECTOR (CHECK FOR OPEN)


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.5L-E Engine Control.Ecd System. Dtc P0115 Engine Coolant Temperature Circuit

  1. Disconnect the engine coolant temperature sensor connector.

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

  1. Connect the GTS to the DLC3.

  1. Turn the ignition switch to ON and turn the GTS on.

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

  1. Read the value.

    OK:
    140°C (284°F) or higher
    Text in Illustration
    *1
    		Engine Coolant Temperature Sensor
    *2
    		ECM
    *a
    		Front view of wire harness connector
    (to Engine Coolant Temperature Sensor)


NG
Go to step 3
OK

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (LandCruiser RM0000012V900EX.html)

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

  1. Disconnect the engine coolant temperature sensor connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    C111-2 - C162-21 (THW)
    		Always
    		Below 1 Ω
    C111-1 - C162-29 (ETHW)
    		Always
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (LandCruiser RM000000VW203FX.html)

4.CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT)


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.5L-E Engine Control.Ecd System. Dtc P0115 Engine Coolant Temperature Circuit

  1. Disconnect the engine coolant temperature sensor connector.

  1. Connect the GTS to the DLC3.

  1. Turn the ignition switch to ON and turn the GTS on.

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

  1. Read the value.

    OK:
    -40°C (-40°F)
    Text in Illustration
    *1
    		Engine Coolant Temperature Sensor
    *2
    		ECM


NG
Go to step 5
OK

REPLACE ENGINE COOLANT TEMPERATURE SENSOR (LandCruiser RM0000012V900EX.html)

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

  1. Disconnect the engine coolant temperature sensor connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection
    		Condition
    		Specified Condition
    C111-2 or C162-21 (THW) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (LandCruiser RM000000VW203FX.html)