DTC P0115 Engine Coolant Temperature Circuit Malfunction; DTC P0117 Engine Coolant Temperature Circuit Low Input; DTC P0118 Engine Coolant Temperature Circuit High Input: Wiring Diagram

WARNING: This page is about a different car, the 2006 Lexus IS 350. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Engine Coolant Temperature Circuit Malfunction - Wiring Diagram

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Read freeze frame data using the intelligent tester. 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 (See FREEZE FRAME DATA ).

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: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / 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

RESULT REFERENCE

Temperature Displayed	Proceed to
-40°C (-40°F)	A
140°C (284°F) or higher	B
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).

B : Go to step 4

C : CHECK FOR INTERMITTENT PROBLEMS

A : GO TO NEXT STEP

CHECK ENGINE COOLANT TEMPERATURE SENSOR (CHECK FOR OPEN IN SENSOR)
1. Confirm good connection at sensor.
2. Disconnect the E40 Engine Coolant Temperature (ECT) sensor connector.
3. Connect terminals 1 and 2 of the ECT sensor connector on the wire harness side.
4. Connect the intelligent tester to the DLC3.
5. Turn the engine switch on (IG).
6. Turn the tester on.
7. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
8. Read the value displayed on the tester.
  
  Fig 2: Identifying E40 Engine Coolant Temperature (ECT) Sensor Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard: 140°C (284°F) or higher.
9. Reconnect the ECT sensor connector.
OK : REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG : GO TO NEXT STEP
CHECK ECM (CHECK FOR OPEN IN ECM)
1. Confirm good connection at ECM.
2. Disconnect the E40 ECT sensor connector.
3. Connect terminals THW and ETHW of the E5 ECM connector.
  HINT:
  
  Before checking, do visual and contact pressure checks on the ECM connector.
4. Connect the intelligent tester to the DLC3.
5. Turn the engine switch on (IG).
6. Turn the tester on.
7. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
8. Read the value displayed on the tester.
  
  Fig 3: Connecting Terminals THW And ETHW Of E5 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard: 140°C (284°F) or higher.
9. Reconnect the ECT sensor connector.
OK : REPAIR OR REPLACE HARNESS OR CONNECTOR

NG : REPLACE ECM
CHECK ENGINE COOLANT TEMPERATURE SENSOR (CHECK FOR SHORT IN SENSOR)
1. Disconnect the E40 ECT sensor connector.
2. Connect the intelligent tester to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the tester on.
5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
6. Read the value displayed on the tester.
  
  Fig 4: Identifying E40 ECT Sensor Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard: -40°C (-40°F)
7. Reconnect the ECT sensor connector.
OK : REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG : GO TO NEXT STEP
CHECK ECM (CHECK FOR SHORT IN ECM)
1. Disconnect the E5 ECM connector.
2. Connect the intelligent tester to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the tester on.
5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
6. Read the value displayed on the tester.
  
  Fig 5: Identifying E5 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard: -40°C (-40°F)
7. Reconnect the ECM connector.
OK : REPAIR OR REPLACE HARNESS OR CONNECTOR

NG : REPLACE ECM