Inspection Procedure

HINT:

Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

1. READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (MASS AIR FLOW RATE) 
   1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
   2. Start the engine.
   3. Push the hand-held tester or the OBD II scan tool main switch ON.
   4. Select the item "DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAF" and read its value displayed on the hand-held tester or the OBD II scan tool.

      Result: 

      RESULT REFERENCE
      
      

      Air Flow Rate (gm/s)	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 opened or closed.

   1. B : Go to step   6 
   2. C : CHECK FOR INTERMITTENT PROBLEMS (See  CHECK FOR INTERMITTENT PROBLEMS  ) 
   3. A : GO to next step 
2. INSPECT MASS AIR FLOW SENSOR (POWER SOURCE) 
   Fig 1: Identifying Mass Air Flow Sensor Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Turn the ignition switch ON.
   2. Disconnect the M1 mass air flow sensor connector.
   3. Measure the voltage between the terminal of the wire harness side connector and body ground.

      Standard: 

      TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      B (M1-1) - Body ground	9 to 14 V

   4. Reconnect the mass air flow sensor connector.
   • NG : Go to step   5 
   • OK : Go to next step 
3. INSPECT ECM (VG VOLTAGE) 
   Fig 2: Identifying E4 ECM Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Start the engine.
   2. Measure the voltage between the terminals of the E4 ECM connector.

   HINT:

   The shift position should be P or N and the A/C switch should be turned OFF.

   Standard: 

   TESTER CONNECTION AND SPECIFIED CONDITION
   
   

   Tester Connection	Condition	Specified Condition
   VG (E4-24) - EVG (E4-32)	Engine is idling	1.1 to 1.5V

   • NG : REPLACE ECM (See  REPLACEMENT  ) 
   • OK : Go to next step 
4. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW SENSOR - ECM) 
   1. Disconnect the M1 mass air flow sensor connector.
   2. Disconnect the E4 ECM connector.
   3. Check the resistance between the wire harness side connectors.
      Fig 3: Identifying M1 Mass Air Flow Sensor Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard (Check for open): 

      TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      VG(M1-3)-VG (E4-24)	Below 1 Ω
      E2G(M1-2)-EVG(E4-32)

      Standard (Check for short): 

      TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      VG (M1-3) or VG (E4-24) - Body ground	10 kΩ or higher

   4. Reconnect the mass air flow sensor connector.
   5. Reconnect the ECM connector.
   Fig 4: Identifying E4 ECM Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 
   • OK : REPLACE MASS AIR FLOW SENSOR 
5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW SENSOR - EFI RELAY) 
   1. Remove the EFI relay from the engine room R/B.
   2. Disconnect the M1 mass air flow sensor connector.
   3. Check the resistance between the wire harness side connectors.

      Standard (Check for open): 

      TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      +B(M1-1)-EFI relay (3)	Below 1 Ω

      Fig 5: Identifying EFI Relay Location

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard (Check for short): 

      TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      +B (M1-1) or EFI relay (3) - Body ground	10 kΩ or higher

   4. Reconnect the mass air flow sensor connector.
   5. Reinstall the EFI relay.
   Fig 6: Identifying Mass Air Flow Sensor Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 
   • OK : CHECK FOR  ECM POWER SOURCE CIRCUIT  
6. INSPECT ECM (SENSOR GROUND) 
   1. Check the resistance between the terminals of the E4 ECM connector.

      Standard: 

      TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      EVG (E4-32) - Body ground	Below Ω

      Fig 7: Identifying E4 ECM Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • NG : REPLACE ECM (See  REPLACEMENT  ) 
   • OK : Go to next step 
7. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW SENSOR - ECM) 
   1. Disconnect the M1 mass air flow sensor connector.
   2. Disconnect the E4 ECM connector.
   3. Check the resistance between the wire harness side connectors.

      Standard (Check for open): 

      TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      VG (M1-3)-VG(E4-24)	Below 1 Ω
      E2G (M1-2) - EVG (E4-32)

      Fig 8: Identifying M1 Mass Air Flow Sensor Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard (Check for short): 

      TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      VG (M1-3) or VG (E4-24) - Body ground	10 kΩ or higher

   4. Reconnect the ECM connector.
   5. Reconnect the mass air flow sensor connector.
   Fig 9: Identifying E4 ECM Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 
   • OK : REPLACE MASS AIR FLOW SENSOR