Inspection Procedure

HINT:

Read freeze frame data using the intelligent tester. 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 INTELLIGENT TESTER (MASS AIR FLOW RATE) 
   1. Connect the intelligent tester to the DLC3.
   2. Start the engine.
   3. Turn the tester on.
   4. On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAR
   5. Read the values displayed on the tester.

      Result 

      MASS AIR FLOW RATE RESULT REFERENCE
      
      

      Mass Air Flow Rate (gm/s)	Proceed to
      0.0	A
      271.0 or more	B
      Between 1.0 and 270.0 (*)	C
      HINT: *: The value must change 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 MAF meter connector.
   2. Turn the ignition switch to the ON position.
   3. Measure the voltage according to the value (s) in the table below.

      Standard voltage 

      MASS AIR FLOW METER TESTER CONNECTION AND SPECIFIED CONDITION
      
      

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

   NG: Go to step   5 

   Fig 1: Identifying M1 MAF Meter Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: GO TO NEXT STEP 

3. INSPECT ECM (VG VOLTAGE) 
   1. Start the engine.
   2. Measure the voltage according to the value (s) in the table below.

      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 

      ECM TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Condition	Specified Condition
      VG (E7-28) - E2G (E7-30)	Engine Idling	0.5 to 3.0 V

   NG: Go to step 4 

   Fig 2: Identifying E7 Connector E2G And VG Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE ECM 

4. CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM) 
   1. Disconnect the M1 MAF meter connector.
      Fig 3: Identifying M1 MAF Meter Connector E2G And VG Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Disconnect the E7 ECM connector.
   3. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      WIRE HARNESS TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      VG (M1-3) - VG (E7-28)	Below 1 Ω
      E2G (M1-2) - E2G (E7-30)	Below 1 Ω
      VG (M1-3) or VG (E7-28) - Body ground	10 kΩ or higher

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   Fig 4: Identifying E7 ECM Connector E2G And VG Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE MASS AIR FLOW METER 

5. CHECK WIRE HARNESS (MASS AIR FLOW METER - EFI RELAY [Marking: EFI]) 
   1. Inspect the EFI fuse.
      1. Remove the EFI fuse from the engine room relay block.
      2. Measure the EFI fuse resistance.

         Standard resistance: 

         Below 1 Ω 

      3. Reinstall the EFI fuse.
   2. Remove the EFI relay from the engine room relay block.
   3. Disconnect the M1 MAF meter connector.
   4. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      WIRE HARNESS TESTER CONNECTION AND SPECIFIED CONDITION
      
      

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

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   Fig 5: Identifying EFI Fuse And EFI Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: INSPECT ECM POWER SOURCE CIRCUIT 

6. INSPECT ECM (SENSOR GROUND) 
   1. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      ECM TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      E2G (E7-30) - Body ground	Below 1 Ω

   NG: REPLACE ECM 

   Fig 6: Identifying E7 ECM Connector E2G Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: GO TO NEXT STEP 

7. CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM) 
   1. Disconnect the M1 MAF meter connector.
      Fig 7: Identifying M1 MAF Meter Connector E2G And VG Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Disconnect the E7 ECM connector.
   3. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      WIRE HARNESS TESTER CONNECTION AND SPECIFIED CONDITION
      
      

      Tester Connection	Specified Condition
      VG (M1-3) - VG (E7-28)	Below 1 Ω
      E2G (M1-2) - E2G (E7-30)	Below 1 Ω
      VG (M1-3) or VG (E7-28) - Body ground	10 kΩ or higher

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   Fig 8: Identifying E7 ECM Connector E2G And VG Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE MASS AIR FLOW METER