Inspection Procedure

HINT:

Read freeze frame data using 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 (MASS AIR FLOW RATE) 
   1. Connect Techstream to the DLC3.
   2. Start the engine.
   3. Turn the tester ON.
   4. Select the following menu items: Powertrain / Engine and ECT / Data List / MAF.
   5. Read the values displayed on the tester.

      Result 

      RESULT REFERENCE
      
      

      Mass Air Flow Rate (g/sec.)	Proceed To
      0.0	A
      271.0 or more	B
      Between 1.0 and 270.0 (*1)	C
      HINT: *1: The value must change when the throttle valve is open or closed with the engine running.

   B:  Go to step  6

   C: CHECK FOR INTERMITTENT PROBLEMS 

   A: Go to Next Step 

2. INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE) 
   1. Disconnect the B1 Mass Air Flow (MAF) meter connector.
   Fig 1: Identifying Mass Air Flow Meter Connector Terminals
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Turn the ignition switch ON.
   3. Measure the voltage between the terminal of the wire harness side connector and body ground.

      Standard voltage 

      VOLTAGE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B1-3 (+B) - Body ground	9 to 14V

   4. Reconnect the MAF meter connector.

   NG:  Go to step  5

   OK: Go to Next Step 

3. INSPECT MASS AIR FLOW METER (VG VOLTAGE) 
   1. Output voltage inspection.
      1. Apply battery voltage across terminals +B and E2G.
      2. Connect the positive (+) tester probe to terminal VG, and negative (-) tester probe to terminal E2G.
      3. Measure the voltage.

         Standard voltage 

         VOLTAGE SPECIFICATION
         
         

         Tester Connections	Specified Conditions
         5 (VG) - 4 (E2G)	0.2 to 4.9 V

         Fig 2: Identifying Mass Air Flow Meter Connector Terminals

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPLACE MASS AIR FLOW METER 

   OK: Go to Next Step 

4. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
   1. Disconnect the B1 MAF meter connector.
   2. Disconnect the B30 ECM connector.
   3. Measure the resistance.

      Standard resistance (Check for open) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B1-5 (VG) - B30-118 (VG)	Below 1 Ω
      B1-4 (E2G) - B30-116 (E2G)	Below 1 Ω

      Standard resistance (Check for short) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B1-5 (VG) or B30-118 (VG) - Body ground	10 kΩ or higher

   4. Reconnect the MAF meter connector.
   5. Reconnect the ECM connector.
   Fig 3: Identifying Mass Air Flow Meter And ECM Connector Terminals
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: REPLACE ECM 

5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY) 
   1. Check the EFI No. 1 fuse.
   2. Disconnect the B1 MAF meter connector.
   3. Remove the integration relay from the engine room No. 1 relay block.
   4. Check the resistance.

      Standard resistance (Check for open) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B1-3 (+B) - 1A-4	Below 1 Ω

      Standard resistance (Check for short) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B1-3 (+B) or 1A-4 - Body ground	10 kΩ or higher

   5. Reconnect the MAF meter connector.
   6. Reinstall the integration relay.
      Fig 4: Identifying Mass Air Flow Meter Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: CHECK ECM POWER SOURCE CIRCUIT 

6. CHECK HARNESS AND CONNECTOR (SENSOR GROUND) 
   1. Disconnect the B1 MAF meter connector.
   2. Measure the resistance.

      Standard resistance 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B1-4 (E2G) - Body ground	Below 1 Ω

      Fig 5: Identifying Mass Air Flow Meter Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE MASS AIR FLOW METER 

   NG: Go to Next Step 

7. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
   1. Disconnect the B1 MAF meter connector.
   2. Disconnect the B30 ECM connector.
   3. Measure the resistance.

      Standard resistance (Check for open) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B1-5 (VG) - B30-118 (VG)	Below 1 Ω
      B1-4 (E2G) - B30-116 (E2G)	Below 1 Ω

      Standard resistance (Check for short) 

      RESISTANCE SPECIFICATION
      
      

      Tester Connections	Specified Conditions
      B1-5 (VG) or B30-118 (VG) - Body ground	10 kΩ or higher

   4. Reconnect the MAF meter connector.
   5. Reconnect the ECM connector.
   Fig 6: Identifying Mass Air Flow Meter And ECM Connector Terminals
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: REPLACE ECM