Inspection Procedure

HINT:

Read freeze frame data using a Techstream. Freeze frame data records 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.

      OK: 

      Same as actual Intake Air Temperature (IAT). 

      Result 

      RESULT REFERENCE
      
      

      Result	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 mass air flow meter connector.
   2. Connect terminals 1 (THA) and 2 (E2) of the MAF meter wire harness side connector.
   3. Connect a 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 value: 

      140°C(284°F) or higher 

   8. Reconnect the mass air flow meter connector.

   NG: Go to step 3 

   Fig 1: Identifying Mass Air Flow Meter Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : CONFIRM GOOD CONNECTION TO SENSOR. IF 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 

      RESISTANCE SPECIFICATION
      
      

      Tester Connection	Condition	Specified Condition
      C23-1 (THA) -C19-65 (THA)	Always	Below 1 Ω
      C23-2 (E2) - C19-88 (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 

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM  (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE )

4. READ VALUE USING TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS) 
   1. Disconnect the mass air flow meter connector.
   2. Connect a 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 value: 

      -40°C (-40°F) 

   7. Reconnect the mass air flow meter connector.

   NG: Go to step 5 

   Fig 3: Checking For Short In Wire Harness

   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 

      RESISTANCE SPECIFICATION
      
      

      Tester Connection	Condition	Specified Condition
      C23-1 (THA) or C19-65 (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 

   Fig 4: Identifying Mass Air Flow Meter And ECM Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : REPLACE ECM  (See ELECTRONIC CIRCUIT INSPECTION PROCEDURE )