Inspection Procedure

HINT:

Read freeze frame data using a Techstream. Freeze frame data record 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, if the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.

1. READ VALUE USING TECHSTREAM (ENGINE COOLANT TEMPERATURE) 
   1. Connect a Techstream to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the tester ON.
   4. Select the following menu items: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
   5. Read the value displayed on the tester.

      Standard: 

      75°C to 100°C (167°F to 212°F) with warm engine. 

      Result 

      RESULT CHART
      
      

      Temperature Displayed	Proceed To
      -40°C (-40°F)	A
      140°C (284°F) or higher	B
      75°C to 100°C (167°F to 212°F)	C

      HINT:

      • If there is an open circuit, the tester indicates -40°C (-40°F).
      • If there is a short circuit, the tester indicates 140°C (284°F) or higher.

   B:  Go to step  4

   C: CHECK FOR INTERMITTENT PROBLEMS (See  CHECK FOR INTERMITTENT PROBLEMS   ) 

   A: Go to next step 

2. READ VALUE USING TECHSTREAM (CHECK FOR OPEN IN WIRE HARNESS) 
   1. Disconnect the C19 Engine Coolant Temperature (ECT) sensor connector.
   Fig 1: Identifying ECT Sensor Connector
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Connect terminals 1 and 2 of the ECT sensor connector on the wire harness side.
   3. Connect the Techstream to the DLC3.
   4. Turn the ignition switch to ON.
   5. Turn the tester ON.
   6. Select the following menu items: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
   7. Read the value displayed on the tester.

      Standard: 

      140°C (284°F) or higher. 

   8. Reconnect the ECT sensor connector.

   OK: CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE ENGINE COOLANT TEMPERATURE SENSOR (See  REMOVAL   ) 

   NG: Go to next step 

3. CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR ECM) 
   1. Disconnect the C19 ECT sensor connector.
   Fig 2: Identifying C19 ECT Sensor Connector And C20 ECM Connector Terminals
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Disconnect the C20 ECM connector.
   3. Check the resistance.

      Standard resistance 

      TESTER CONNECTIONS SPECIFIED CONDITIONS CHART
      
      

      Tester Connections	Specified Conditions
      THW (C19-2) - THW (C20-97)	Below 1 Ω
      E2 (C19-1) - ETHW (C20-96)

   4. Reconnect the ECT sensor connector.
   5. Reconnect the ECM connector.

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: GOOD CONNECTION TO ECM. IF OK, REPLACE ECM (See  REMOVAL   ) 

4. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS) 
   1. Disconnect the C19 ECT sensor connector.
   Fig 3: Identifying ECT Sensor Circuit Diagram
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Connect the Techstream to the DLC3.
   3. Turn the ignition switch to ON.
   4. Turn the tester ON.
   5. Select the following menu items: Powertrain / Engine and ECT / Data List / All Data / 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 (See  REMOVAL   ) 

   NG: Go to next step 

5. CHECK HARNESS AND CONNECTOR (ENGINE COOLANT TEMPERATURE SENSOR ECM) 
   1. Disconnect the C19 ECT sensor connector.
   Fig 4: Identifying C19 ECT Sensor And C20 ECM Connector Terminals
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Disconnect the C20 ECM connector.
   3. Check the resistance.

      Standard resistance 

      TESTER CONNECTIONS SPECIFIED CONDITIONS CHART
      
      

      Tester Connections	Specified Conditions
      THW (C19-2) or THW (C20-97) - Body ground	10 kΩ or higher

   4. Reconnect the ECT sensor connector.
   5. Reconnect the ECM connector.

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: REPLACE ECM (See  REMOVAL   )