Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus IS 350. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

Read freeze frame data using Techstream. 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 Techstream to the DLC3.
Turn the engine switch on (IG).
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / 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

RESULT REFERENCE CHART

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, Techstream indicates -40°C (-40°F).
If there is a short circuit, Techstream indicates 140°C (284°F) or higher.

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 Techstream to the DLC3.
5. Turn the engine switch on (IG).
6. Turn the tester on.
7. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
8. Read the value displayed on the tester.
  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 Techstream to the DLC3.
5. Turn the engine switch on (IG).
6. Turn the tester on.
7. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
8. Read the value displayed on the tester.
  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 Techstream to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the tester on.
5. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
6. Read the value displayed on the tester.
  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 Techstream to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the tester on.
5. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
6. Read the value displayed on the tester.
  Standard:
  
  -40°C (-40°F)
7. Reconnect the ECM connector.
OK: REPAIR OR REPLACE HARNESS OR CONNECTOR

NG: REPLACE ECM