Inspection Procedure

HINT:

• If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
• Read freeze frame data using Techstream. 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 TECHSTREAM (INTAKE AIR TEMPERATURE) 
   1. Connect Techstream to the DLC3.
   2. Turn the ignition switch on (IG).
   3. Turn the tester on.
   4. Select the following menu items: Powertrain / Engine and ECT / Data List / Intake Air.
   5. Read the value displayed on the tester.

      Standard: Same as actual intake air temperature. 

   Result 

   RESULT TABLE
   
   

   Temperature Displayed	Proceed to
   -40°C (-40°F)	A
   140°C (284°F) or higher	B
   Same as actual intake air temperature	C

   HINT:

   • If there is an open circuit, Techstream indicates -40°C (-40°F).
   • If there is a short circuit, Techstream 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 OF TECHSTREAM (CHECK FOR OPEN IN WIRE HARNESS) 
   1. Disconnect the mass air flow meter connector.
   2. Connect terminals THA and E2 of the mass air flow meter wire harness side connector.
   3. Connect Techstream to the DLC3.
   4. Turn the ignition switch on (IG).
   5. Turn the tester on.
   6. Select the following menu items: Powertrain / Engine and ECT / Data List / Intake Air.
   7. Read the value displayed on the tester.

      Standard: 140°C (284°F) or higher 

   8. Reconnect the mass air flow meter connector.
      Fig 1: Identifying Mass Air Flow Meter Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG:  Go to step  3

   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: Check for open 

      STANDARD RESISTANCE: CHECK FOR OPEN
      
      

      Tester Connection	Condition	Specified Condition
      B1-22 (THA) - B10-1 (THA)	Always	Below 1 Ω
      B1-28 (E2) - B10-2 (E2)	Always	Below 1 Ω

      Check for short 

      STANDARD RESISTANCE: CHECK FOR SHORT
      
      

      Tester Connection	Condition	Specified Condition
      B1-22 (THA) or B10-1 (THA) - Body ground	Always	10 kΩ or higher
      B1-28 (E2) or B10-2 (E2) - Body ground	Always	10 kΩ or higher

   4. Reconnect the mass air flow meter connector.
   5. Reconnect the ECM connector.
   Fig 2: Identifying Harness & Connector (Mass Air Flow Meter - ECM)
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPLACE ECM  (See REMOVAL )

   OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM) 

4. READ VALUE OF TECHSTREAM (CHECK FOR SHORT IN WIRE HARNESS) 
   1. Disconnect the mass air flow meter connector.
   2. Connect Techstream to the DLC3.
   3. Turn the ignition switch on (IG).
   4. Turn the tester on.
   5. Select the following menu items: Powertrain/Engine and ECT/Data List/Intake Air.
   6. Read the value displayed on the tester.

      Standard: -40°C (-40°F) 

   7. Reconnect the mass air flow meter connector.
      Fig 3: Identifying Mass Air Flow Meter Circuit

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG:  Go to step  5

   OK: REPLACE MASS AIR FLOW METER 

5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
   1. Disconnect the mass air flow meter connector.
   2. Connect Techstream to the DLC3.
   3. Turn the ignition switch on (IG).
   4. Turn the tester on.
   5. Select the following menu items: Powertrain / Engine and ECT / Data List / Intake Air.
   6. Read the value displayed on the tester.

      Standard: -40°C (-40°F) 

   7. Reconnect the mass air flow meter connector.
      Fig 4: Identifying Harness & Connector (Mass Air Flow Meter - ECM)

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: REPLACE ECM  (See REMOVAL

   OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)