Inspection Procedure

HINT:

Read freeze frame data using an intelligent tester or OBD II scan tool. 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 OF INTELLIGENT TESTER OR OBD II SCAN TOOL (MASS AIR FLOW RATE) 
   1. Connect an intelligent tester or OBD II scan tool to the DLC3.
   2. Start the engine.
   3. Turn the tester or scan tool ON.
   4. On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAF.
   5. Read the values displayed on the tester.
   6. If using an OBD II scan tool, refer to the instruction information.

      Result 

      RESULT
      
      

      Mass Air Flow Rate (g/sec)	Proceed to
      0.0	A
      271.0 or more	B
      Between 1.0 and 270.0 ((1))	C
      (1) The value must be changed when the throttle valve is open or closed.

   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 M1 Mass Air Flow (MAF) meter connector.
   2. Turn the ignition switch to ON.
   3. Measure the voltage between the terminal of the wire harness side connector and body ground.

      Standard voltage 

      TESTER CONNECTIONS - SPECIFIED CONDITIONS (1 OF 2)
      
      

      Tester Connections	Specified Conditions
      +B (M1-1) - Body ground	Between 9 V and 14 V

   4. Reconnect the MAF meter connector.

   NG : Go to step   5 

   Fig 1: Inspecting Mass Air Flow Meter (Power Source Voltage)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : GO TO NEXT STEP 

3. INSPECT ECM (VG VOLTAGE) 
   1. Start the engine.
   2. Measure the voltage between the terminals of the E4 ECM connector.

      HINT:

      The transmission gear selector lever should be in the P or N position and the A/C switch should be turned OFF.

      Standard voltage 

      TESTER CONNECTIONS - SPECIFIED CONDITIONS (2 OF 2)
      
      

      Tester Connections	Conditions	Specified Conditions
      VG (E3-30) - EVG (E3-29)	Engine idling	Between 0.5 V and 3.0 V

   OK : REPLACE ECM 

   Fig 2: Inspecting ECM (VG Voltage)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG : GO TO NEXT STEP 

4. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
   1. Disconnect the M1 MAF meter connector.
   2. Disconnect the E4 ECM connector.
   3. Check the resistance.

      Standard resistance (Check for open) 

      TESTER CONNECTIONS - SPECIFIED CONDITIONS (CHECK FOR OPEN)
      
      

      Tester Connections	Specified Conditions
      VG (M1-3) - VG (E3-30)	Below 1
      E2G (M1-2) - EVG (E3-29)	Below 1

      Standard resistance (Check for short) 

      TESTER CONNECTIONS - SPECIFIED CONDITIONS (CHECK FOR SHORT)
      
      

      Tester Connections	Specified Conditions
      VG (M1-3) or VG (E3-30) - Body ground	10 k or higher

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

   NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 

   Fig 3: Checking Harness And Connector (Mass Air Flow Meter - ECM)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : REPLACE MASS AIR FLOW METER 

5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI RELAY) 
   1. Remove the EFI relay from the engine room R/B.
   2. Disconnect the M1 MAF meter connector.
   3. Check the resistance.

      Standard resistance (Check for open) 

      TESTER CONNECTIONS - SPECIFIED CONDITIONS (CHECK FOR OPEN)
      
      

      Tester Connections	Specified Conditions
      +B (M1-1) - EFI relay (3)	Below 1

      Standard resistance (Check for short) 

      TESTER CONNECTIONS - SPECIFIED CONDITIONS (CHECK FOR SHORT)
      
      

      Tester Connections	Specified Conditions
      +B (M1-1) or EFI relay (3) - Body ground	10 k or higher

   4. Reconnect the MAF meter connector.
   5. Reinstall the EFI relay.

   NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : INSPECT ECM POWER SOURCE CIRCUIT 

6. INSPECT ECM (SENSOR GROUND) 
   1. Check the resistance.

      Standard resistance 

      TESTER CONNECTIONS - SPECIFIED CONDITIONS
      
      

      Tester Connections	Specified Conditions
      EVG (E3-29) - Body ground	Below 1

   NG : REPLACE ECM 

   Fig 5: Inspecting ECM (Sensor Ground)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : GO TO NEXT STEP 

7. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
   1. Disconnect the M1 MAF meter connector.
   2. Disconnect the E4 ECM connector.
   3. Check the resistance.

      Standard resistance (Check for open) 

      TESTER CONNECTIONS - SPECIFIED CONDITIONS (CHECK FOR OPEN)
      
      

      Tester Connections	Specified Conditions
      VG (M1-3) - VG (E3-30)	Below 1
      E2G (M1-2) - EVG (E3-29)	Below 1

      Standard resistance (Check for short) 

      TESTER CONNECTIONS - SPECIFIED CONDITIONS (CHECK FOR SHORT)
      
      

      Tester Connections	Specified Conditions
      VG (M1-3) or VG (E3-30) - Body ground	10 k or higher

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

   NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 

   Fig 6: Checking Harness And Connector (Mass Air Flow Meter - ECM)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK : REPLACE MASS AIR FLOW METER