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 (INTAKE AIR 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 / All Data / Intake Air.
   5. Read the value displayed on the tester.

      Standard: 

      Same as actual Intake Air Temperature (IAT). 

      Result 

      RESULT CHART
      
      

      Temperature Displayed	Proceed To
      -40°C (-40°F)	A
      140°C (284°F) or higher	B
      Same as actual IAT	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 C26 Mass Air Flow (MAF) meter connector.
   2. Connect terminals THA and E2 of the MAF meter wire harness side connector.
   Fig 1: Identifying Terminals THA And E2 Of MAF Meter Wire Harness Side Connector
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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 / All Data / Intake Air.
   7. Read the value displayed on the tester.

      Standard: 

      140°C (284°F) or higher 

   8. Reconnect the MAF meter connector.

   OK: CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER (See  REMOVAL   ) 

   NG: Go to next step 

3. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
   Fig 2: Identifying Harness And Connector (Mass Air Flow Meter - ECM)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Disconnect the C26 MAF meter connector.
   2. Disconnect the C20 ECM connector.
   3. Check the resistance.

      Standard resistance 

      TESTER CONNECTIONS SPECIFIED CONDITIONS CHART
      
      

      Tester Connections	Specified Conditions
      THA (C26-4) - THA (C20-65)	Below 1 Ω
      E2 (C26-5) - ETHA (C20-88)

   4. Reconnect the MAF meter connector.
   5. Reconnect the ECM connector.

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

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

4. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS) 
   1. Disconnect the C26 MAF meter connector.
   Fig 3: Identifying MAF Meter 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 / All Data / Intake Air.
   6. Read the value displayed on the tester.

      Standard: 

      -40°C (-40°F) 

   7. Reconnect the MAF meter connector.

   OK: REPLACE MASS AIR FLOW METER (See  REMOVAL   ) 

   NG: Go to next step 

5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
   1. Disconnect the C26 MAF meter connector.
   Fig 4: Identifying C26 MAF Meter 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
      THA (C26-4) or THA (C20-65) - Body ground	10 kΩ or higher

   4. Reconnect the MAF meter connector.
   5. Reconnect the ECM connector.

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: REPLACE ECM (See  REMOVAL   )