Inspection Procedure

HINT:

• If DTCs related 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 the hand-held tester or the OBDII scan tool. Freeze frame data records the engine condition when 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 (INTAKE AIR TEMPERATURE) 
   1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
   2. Turn the power switch ON (IG).
   3. Turn the hand-held tester or the OBD II scan tool ON.
   4. On the hand-held tester, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   5. Read the value using the hand-held tester or the OBD II scan tool.
      1. Temperature value: Same as the ambient air temperature. 
      2. Result: 
      INTAKE AIR TEMPERATURE RESULT
      
      

      Temperature Displayed	Proceed to
      -40°C (-40°F)	A
      140°C (284°F)	B
      OK: (Same as ambient air temperature)	C

   HINT:

   • If there is an open circuit, the hand-held tester or the OBD II scan tool indicates -40°C (-40°F).
   • If there is a short circuit, the hand-held tester or the OBD II scan tool indicates 140°C (284°F).

   B: Go to step   4 

   C CHECK FOR INTERMITTENT PROBLEMS (See  CHECK FOR INTERMITTENT PROBLEMS   ) 

   A: GO TO NEXT STEP 

2. READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (CHECK FOR OPEN IN WIRE HARNESS) 
   1. Disconnect the M1 mass air flow meter connector.
   2. Connect terminals THA and E2 of the mass air flow meter wire harness side connector.
   3. Turn the power switch ON (IG).
   4. On the hand-held tester, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR. Read the value.
      1. OK 
      2. Temperature value: 140°C (284°F) 
      Fig 1: Identifying Terminals Connection THA And E2 Of Mass Air Flow Harness Side Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   5. Reconnect the mass air flow meter connector.
      Fig 2: Locating Mass Air Flow Meter Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: CONFIRM GOOD CONNECTION AT SENSOR. IF OK, REPLACE MASS AIR FLOW SENSOR 

   NG: GO TO NEXT STEP 

3. READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (CHECK FOR OPEN IN ECM) 
   1. Disconnect the M1 mass air flow meter connector.
   2. Connect terminals THA and E2 of the E4 ECM connector.

      HINT:

      Before checking, do a visual and contact pressure check for the ECM connector.

      Fig 3: Identifying Terminal Connection THA And E2 & E4 ECM

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. Turn the power switch ON (IG).
   4. On the hand-held tester, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR. Read the value.
      1. OK: 
      2. Temperature value: 140°C (284°F) 
   5. Reconnect the mass air flow meter connector.
      Fig 4: Locating THA And E2 Terminal Of ECM Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   NG: GO TO NEXT STEP 

   CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM (See  ENGINE CONTROL SYSTEM  ) 

4. READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN WIRE HARNESS) 
   1. Disconnect the M1 mass air flow meter connector.
   2. Turn the power switch ON (IG).
   3. On the hand-held tester, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR. Read the value.
      1. OK: 
      2. Temperature value: -40°C (-40°F) 
   4. Reconnect the mass air flow meter connector.

   OK: REPLACE MASS AIR FLOW METER 

   Fig 5: Checking For Short In Wire Harness

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   NG: GO TO NEXT STEP 

5. READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN ECM) 
   1. Disconnect the E4 ECM connector.
   2. Turn the power switch ON (IG).
   3. On the hand-held tester, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR. Read the value.
      1. OK: 
      2. Temperature value: -40°C (-40°F) 
   4. Reconnect the ECM connector.
      Fig 6: Checking For Short In ECM

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 7: Reconnecting ECM Connectors

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   NG 

   REPLACE ECM (See  ENGINE CONTROL SYSTEM  )