Inspection Procedure

INSPECTION PROCEDURE

NOTE: If Diagnostic Trouble Codes "P0110" (intake air temperature circuit malfunction), "P0115" (engine coolant temperature circuit malfunction), "P0120" (throttle position circuit malfunction) are output simultaneously, E2 (sensor ground) may be open.

1. Connect the OBDII scan tool or LEXUS hand-held tester, and read value of engine coolant temperature.
- Remove the fuse cover on the instrument panel.





- Connect the OBDII scan tool or LEXUS hand-held tester to the Data Link Connector 3.
- Turn Ignition Switch ON and OBDII scan tool or LEXUS hand-held tester main switch ON.
- Read temperature value on the OBDII scan tool or LEXUS hand-held tester.
- Temperature should read the same as actual engine coolant temperature.
- If OK check for intermittent problems (loose connectors, etc.).
- If -40°C (-40°F) go to step 2.
- If 120°C (248°F) or more go to step 4.
2. Check for open in harness or Engine Control module.
- Disconnect the Engine Coolant Temperature Sensor connector.





- Connect sensor wire harness terminals together.
- Turn Ignition Switch ON.
- Read temperature value on the OBDII scan tool or LEXUS hand-held tester.

Temperature value: 120°C (248°F) or more.

- If not OK proceed to step 3.
- If OK Confirm good connection at sensor. If OK, replace Engine Coolant Temperature Sensor.
3. Check for open in harness or Engine Control module.
- Remove glove compartment.





- Connect between terminals THW and E2 of Engine Control module E8 connector.

NOTE: Engine Coolant Temperature Sensor connector is disconnected. Before checking, do a visual and contact pressure check for the Engine Control Module connector.

- Turn Ignition Switch ON.
- Read temperature value on the OBDII scan tool or LEXUS hand-held tester.

Temperature value: 120°C (248°F) or more.

- If OK open in harness between terminals E2 or THW, repair or replace harness.
- If not OK confirm good connection at Engine Control Module. If OK, replace Engine Control Module.
4. Check for short in harness and Engine Control Module.





- Disconnect the Engine Coolant Temperature Sensor connector.
- Turn Ignition Switch ON.
- Read temperature value on the OBDII scan tool or LEXUS hand-held tester

Temperature value: -40°C (-40°F).

- If not OK proceed to step 5.
- If OK replace Engine Coolant Temperature Sensor.
5. Check for short in harness or Engine Control Module.
- Remove glove compartment.





- Disconnect the E8 connector of Engine Control Module.

NOTE: Engine Coolant Temperature Sensor connector is disconnected.

- Turn Ignition Switch ON.
- Read temperature value on the OBDII scan tool or LEXUS hand-held tester.

Temperature value: -40°C (-40°F).

- If OK repair or replace harness or connector.
- If not OK check and replace Engine Control Module