Inspection Procedure

HINT:

• If other DTCs relating to different systems that have terminal E3 as the ground terminal are output simultaneously, terminal E3 may have an open circuit.
• 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 (See FREEZE FRAME DATA ).

1. READ VALUE OF INTAKE AIR TEMPERATURE SENSOR (INTAKE AIR) 
   1. Connect the intelligent tester to the DLC3.
   2. Turn the engine switch on (IG).
   3. Turn the tester on.
   4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   5. Read the value displayed on the tester.

      Standard: 

      Same as actual Intake Air Temperature (IAT). 

      Result 

      TEMPERATURE SPECIFICATION
      
      

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

      HINT:

      • If there is an open circuit, the intelligent tester indicates 40°C (-40°F).
      • If there is a short circuit, the intelligent tester indicates 140°C (284°F) or higher.

   B: Go to step  4

   C: CHECK FOR INTERMITTENT PROBLEMS 

   A: Go to next step 

2. CHECK INTAKE AIR TEMPERATURE SENSOR (CHECK FOR OPEN IN SENSOR) 
   1. Confirm good connection of the mass air flow meter.
   2. Disconnect the E29 Mass Air Flow (MAF) meter connector.
   3. Connect terminals THA and E2 of the MAF meter wire harness side connector.
   4. Connect the intelligent tester to the DLC3.
   5. Turn the engine switch on (IG).
   6. Turn the tester on.
   7. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   8. Read the value displayed on the tester.

      Standard: 

      140°C (284°F) or higher 

   9. Reconnect the MAF meter connector.
      Fig 1: Identifying MAF Meter Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE MASS AIR FLOW METER 

   NG: Go to next step 

3. CHECK ECM (CHECK FOR OPEN IN ECM) 
   1. Confirm good connection of the ECM.
   2. Disconnect the E29 MAF meter connector.
   3. Connect terminals THA and E3 of the E5 ECM connector.
      Fig 2: Identifying ECM Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      Before checking, do visual and contact pressure checks on the ECM connector.

   4. Connect the intelligent tester to the DLC3.
   5. Turn the engine switch on (IG).
   6. Turn the tester on.
   7. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   8. Read the value displayed on the tester.

      Standard: 

      140°C (284°F) or higher 

   9. Reconnect the MAF meter connector.

   OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   NG: REPLACE ECM 

4. CHECK INTAKE AIR TEMPERATURE SENSOR (CHECK FOR SHORT IN SENSOR) 
   Fig 3: Identifying Intake Air Temperature Sensor

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Disconnect the E29 MAF meter connector.
   2. Connect the intelligent tester to the DLC3.
   3. Turn the engine switch on (IG).
   4. Turn the tester on.
   5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   6. Read the value displayed on the tester.

      Standard: 

      -40°C (-40°F) or higher 

   7. Reconnect the MAF meter connector.

   OK: REPLACE MASS AIR FLOW METER 

   NG: Go to next step 

5. CHECK ECM (CHECK FOR SHORT IN ECM) 
   1. Disconnect the E5 ECM connector.
      Fig 4: Identifying E5 ECM Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Connect the intelligent tester to the DLC3.
   3. Turn the engine switch on (IG).
   4. Turn the tester on.
   5. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
   6. Read the value displayed on the tester.

      Standard: 

      -40°C (-40°F) or higher 

   7. Reconnect the ECM connector.

   OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   NG: REPLACE ECM