Inspection Procedure

HINT:

• If different DTCs related to different systems that have 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/INTAKE AIR.

   CHECK: 

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

   OK: 

   1. Same as actual intake air temperature. 

   RESULT: 

   RESULT
   
   

   Temperature Displayed	Proceed to
   -40°C (-40°F)	A
   140°C (284°F) or more	B
   OK (Same as air temperature near to the intake)	C

   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.
   3. Turn the ignition switch ON.
   4. 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.

   Fig 1: Checking For Open In Harness Or ECM

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: 

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

   OK: Confirm good connection at sensor. If OK, replace mass air flow meter. 

   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.

      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 ).

      Fig 2: Connecting Terminals THA And E2 Of ECM Connector Together

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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 

   OK: Open in harness between terminal E2 or THA, repair or replace harness. 

   NG: Confirm good connection at ECM. If OK, replace ECM (See  ENGINE CONTROL MODULE (ECM)  ). 

4. Check for short in harness and ECM. 

   PREPARATION: 

   1. Disconnect the mass air flow meter connector.
   Fig 3: Disconnecting Mass Air Flow Meter Connector
   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Turn the ignition switch ON.
   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: -40°C (-40°F) 

   OK: Replace mass air flow meter (See  MASS AIR FLOW (MAF) METER  ). 

   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.

      HINT:

      The mass air flow meter connector is disconnected.

      Fig 4: Disconnecting E4 And E5 Connectors From ECM

      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/INTAKE AIR.

   CHECK: 

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

   OK: 

   1. Temperature value: -40°C (-40°F) 

   OK: Repair or replace harness or connector. 

   NG: Replace ECM (See  ENGINE CONTROL MODULE (ECM)  ).