Inspection Procedure

HINT:

• If different DTCs related to different systems that terminal E2 as the ground terminal are output simultaneously, terminal E2 may be open.
• 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, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

1. Connect OBD II scan tool or hand-held tester, and read value of intake air temperature. 

   PREPARATION: 

   1. Connect the OBD II scan tool or hand-held tester to the DLC3.
   2. Turn the ignition switch ON and push the OBD II scan tool or hand-held tester main switch ON.
   3. When using hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II/DATA LIST/ALL DATA/INTAKE AIR.

   CHECK: 

   Read the temperature on the OBD II scan tool or the hand-held tester.

   OK: 

   Same as the actual intake air temperature. 

   RESULT: 

   Fig 1: Temperature Display Chart

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT:

   • If there is open circuit, the OBD II scan tool or the hand-held tester indicates -40°C (-40°F).
   • If there is short circuit, the OBD II scan tool or the hand-held tester indicates 140°C (284°F) or more.
   • B: Go to step   4 . 
   • C: Check for intermittent problems (See  PRE-CHECK   .) 
   • A: Go to next step. 
2. Check for open in harness or ECM. 

   PREPARATION: 

   1. Disconnect the mass air flow meter connector.
   2. Connect the sensor and wire harness terminals together.
      Fig 2: Connecting Sensor & Wire Harness Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. Turn the ignition switch ON.
   4. When using hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II/DATA LIST/ALL DADA/INTAKE AIR.

   CHECK: 

   Read the temperature on the OBD II scan tool or the hand-held tester.

   OK: 

   Temperature value: 140°C (284°F) or more 

   1. OK: Confirm good connection at sensor, If OK, replace mass air flow meter. 
   2. NG: Go to next step. 
3. Check for open in harness or ECM. 

   PREPARATION: 

   1. Remove the ECM hood (See ENGINE CONTROL MODULE (ECM) ).
   2. Connect terminals THA and E2 of the ECM connector together.
      Fig 3: Connecting Terminals THA & E2 Of ECM Connector

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      The mass air flow meter connector is disconnected. Before checking, do a visual and contact pressure check for the ECM connector (See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).

   3. When using hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR.

   CHECK: 

   Read the temperature value on the OBD II scan tool or hand-held tester.

   OK: 

   Temperature value: 140°C (284°F) or more 

   1. OK: Open in harness between terminal E2 or THA, repair or replace harness. 
   2. NG: Confirm good connection at ECM. If OK, replace ECM (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ). 
4. Check for short in harness and ECM. 

   PREPARATION: 

   1. Disconnect the mass air flow meter connector.
   2. Turn the ignition switch ON.
      Fig 4: Turning Ignition Switch ON

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. When using hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II/DATA LIST/ALL DADA/INTAKE AIR.

   CHECK: 

   Read the temperature on the OBD II scan tool or the hand-held tester.

   OK: 

   Temperature value: -40°C (-40°F) 

   1. OK: Replace mass air flow meter. 
   2. NG: Go to next step. 
5. Check for short in harness or ECM. 

   PREPARATION: 

   1. Remove the ECM hood (See ENGINE CONTROL MODULE (ECM) ).
   2. Disconnect the E4 and E5 connectors from the ECM.
      Fig 5: Disconnecting E4 & E5 Connectors From ECM

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      The mass air flow meter connector is disconnected.

   3. Turn the ignition switch ON.
   4. When using hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II/DATA LIST/ALL DADA/INTAKE AIR.

   CHECK: 

   Read the temperature on the OBD II scan tool or the hand-held tester.

   OK: 

   Temperature value: -40°C (-40°F) 

   1. OK: Repair or replace harness or connector. 
   2. NG: Replace ECM (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ).