Dtc P0115 Engine Coolant Temperature Circuit Malfunction

Lexus IS250 IS220d GSE20 ALE20 4GR-FSE ENGINE CONTROL SYSTEM

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE OF ENGINE COOLANT TEMPERATURE SENSOR (COOLANT TEMP)

CHECK ENGINE COOLANT TEMPERATURE SENSOR (CHECK FOR OPEN IN SENSOR)

CHECK ECM (CHECK FOR OPEN IN ECM)

CHECK ENGINE COOLANT TEMPERATURE SENSOR (CHECK FOR SHORT IN SENSOR)

CHECK ECM (CHECK FOR SHORT IN ECM)

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 is built into the Engine Coolant Temperature (ECT) sensor, of which the resistance value varies according to the ECT.


The structure of the sensor and its connection to the ECM are the same as those of the Intake Air Temperature (IAT) sensor.


  • HINT:
  • When any of DTCs P0115, P0117 and P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the ECT is estimated to be 80°C (176°F) by the ECM. Fail-safe mode continues until a pass condition is detected.
DTC No.Proceed toDTC Detection ConditionTrouble Area
P0115Step 1Open or short in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds (1 trip detection logic)
Open or short in ECT sensor circuit
ECT sensor
ECM
P0117Step 4Short in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds (1 trip detection logic)
Short in ECT sensor
ECT sensor
ECM
P0118Step 2Open in Engine Coolant Temperature (ECT) sensor circuit for 0.5 seconds (1 trip detection logic)
Open in ECT sensor circuit
ECT sensor
ECM
  • HINT:
  • When any of these DTCs are set, check the ECT by entering the following menus on the intelligent tester:Power train / Engine / Data List / Coolant Temp.
Temperature DisplayedMalfunction
-40°C (-40°F)Open circuit
140°C (284°F) or higherShort circuit

WIRING DIAGRAM

Dtc P0115 Engine Coolant Temperature Circuit Malfunction. 4GR-FSE ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

  • HINT:
If other DTCs relating 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 .
1.READ VALUE OF ENGINE COOLANT TEMPERATURE SENSOR (COOLANT TEMP)

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Turn the tester ON.

Enter the following menus: Power train / Engine / Data List / Coolant Temp.

Read the value displayed on the tester.

  • Standard:
  • Between 80°C and 97°C (176°F and 207°F) with warm engine.
  • Result:
  • Temperature DisplayedProceed to
    -40°C (-40°F)A
    140°C (284°F) or higherB
    Between 80°C and 97°C (176°F and 207°F)C
  • HINT:
If there is an open circuit, the intelligent tester indicates -40°C (-40°F).
If there is a short circuit, the intelligent tester indicates 140°C (284°F) or higher.
B
Go to step 4
C
CHECK FOR INTERMITTENT PROBLEMS
A
2.CHECK ENGINE COOLANT TEMPERATURE SENSOR (CHECK FOR OPEN IN SENSOR)
Dtc P0115 Engine Coolant Temperature Circuit Malfunction. 4GR-FSE ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Confirm good connection at the Engine Coolant Temperature (ECT) sensor.

Disconnect the E40 ECT sensor connector.

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

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Turn the tester ON.

Enter the following menus: Power train / Engine / Data List / Coolant Temp.

Read the value displayed on the tester.

  • Standard:
  • 140°C (284°F) or higher.

Reconnect the ECT sensor connector.

OK
REPLACE ENGINE COOLANT TEMPERATURE SENSOR
NG
3.CHECK ECM (CHECK FOR OPEN IN ECM)

Confirm good connection at the ECM.

Dtc P0115 Engine Coolant Temperature Circuit Malfunction. 4GR-FSE ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Disconnect the E40 ECT sensor connector.

Connect terminals THW and E2 of the E3 and E5 ECM connector.

  • HINT:
  • Before checking, do visual and contact pressure checks on the ECM connector.

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Turn the tester ON.

Enter the following menus: Power train / Engine / Data List / Coolant Temp.

Read the value displayed on the tester.

  • Standard:
  • 140°C (284°F) or higher.

Reconnect the ECT sensor connector.

OK
REPAIR OR REPLACE HARNESS OR CONNECTOR
NG
REPLACE ECM
4.CHECK ENGINE COOLANT TEMPERATURE SENSOR (CHECK FOR SHORT IN SENSOR)
Dtc P0115 Engine Coolant Temperature Circuit Malfunction. 4GR-FSE ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Disconnect the E40 ECT sensor connector.

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Turn the tester ON.

Enter the following menus: Power train / Engine / Data List / Coolant Temp.

Read the value displayed on the tester.

  • Standard:
  • -40°C (-40°F)

Reconnect the ECT sensor connector.

OK
REPLACE ENGINE COOLANT TEMPERATURE SENSOR
NG
5.CHECK ECM (CHECK FOR SHORT IN ECM)
Dtc P0115 Engine Coolant Temperature Circuit Malfunction. 4GR-FSE ENGINE CONTROL SYSTEM. Lexus IS250 IS220d GSE20 ALE20

Disconnect the E3 and E5 ECM connectors.

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Turn the tester ON.

Enter the following menus: Power train / Engine / Data List / Coolant Temp.

Read the value displayed on the tester.

  • Standard:
  • -40°C (-40°F)

Reconnect the ECM connector.

OK
REPAIR OR REPLACE HARNESS OR CONNECTOR
NG
REPLACE ECM