Inspection Procedure

HINT:

Read freeze frame data using the 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.

1. READ VALUE USING TECHSTREAM (INTAKE AIR TEMPERATURE) 
   1. Connect the Techstream to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the Techstream on.
   4. Enter the following menus: Powertrain / Engine and ECT / Intake Air.
   5. Read the value displayed on the Techstream.

      OK: Same as actual intake air temperature  .

      Result 

      RESULT CHART
      
      

      Result	Proceed to
      -40°C (-40°F)	A
      140°C (284°F) or higher	B
      Same as actual intake air temperature	C

      HINT:

      • If there is an open circuit, the Techstream indicates 40°C (-40°F).
      • If there is a short circuit, the Techstream 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 mass air flow meter connector.
   2. Connect terminals 1 (THA) and 2 (E2) of the mass air flow meter wire harness side connector.
   3. Connect the Techstream to the DLC3.
   4. Turn the ignition switch to ON.
   5. Turn the Techstream on.
   6. Enter the following menus: Powertrain / Engine and ECT / Intake Air.
   7. Read the value displayed on the Techstream.

      Standard value: 

      140°C (284°F) or higher 

   8. Reconnect the mass air flow meter connector.

      NG: Go to step 3 

      Fig 1: Mass Air Flow Meter Circuit Diagram

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: REPLACE MASS AIR FLOW METER  (See REMOVAL )

3. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
   1. Disconnect the mass air flow meter connector.
   2. Disconnect the ECM connector.
   3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART
      
      

      Tester Connection	Condition	Specified Condition
      B2-1 (THA) - B29-65 (THA)	Always	Below 1 Ω
      B2-2 (E2) - B29-88 (ETHA)	Always	Below 1 Ω

   4. Reconnect the mass air flow meter connector.
   5. Reconnect the ECM connector.

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER ECM) 

      Fig 2: Identifying Mass Air Flow Meter Connector And ECM Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: REPLACE ECM  (See REMOVAL )

4. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS) 
   1. Disconnect the mass air flow meter connector.
   2. Connect the Techstream to the DLC3.
   3. Turn the ignition switch to ON.
   4. Turn the Techstream on.
   5. Enter the following menus: Powertrain / Engine and ECT / Intake Air.
   6. Read the value displayed on the Techstream.

      Standard value: 

      -40°C (-40°F) 

   7. Reconnect the mass air flow meter connector.

      NG: Go to step 5 

      Fig 3: Mass Air Flow Meter Circuit Diagram

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: REPLACE MASS AIR FLOW METER  (See REMOVAL )

5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
   1. Disconnect the mass air flow meter connector.
   2. Disconnect the ECM connector.
   3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART
      
      

      Tester Connection	Condition	Specified Condition
      B2-1 (THA) or B29-65 (THA) - Body ground	Always	10 kΩ or higher

   4. Reconnect the mass air flow meter connector.
   5. Reconnect the ECM connector.

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER ECM) 

      Fig 4: Checking Harness And Connector (Mass Air Flow Meter - ECM)

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK: REPLACE ECM  (See REMOVAL )