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, as well as other data from the time when a 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 menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL DADA / INTAKE AIR.

   CHECK: 

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

   OK: 

   Same as actual intake air temperature and temperature displayed on the hand-held tester or OBD II scan tool. 

   RESULT: 

   RESULT
   
   

   Displayed Temperature	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.
   1. B: Go to step   4 . 
   2. C: Check for intermittent problems (See  PRE-CHECK   ). 
   3. 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 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 DADA / 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 

   Fig 1: Checking For Open In Harness Or ECM

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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 cover.
   2. Connect between terminals THA and EVG of the ECM connector.
   3. Turn the ignition switch ON.

      HINT:

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

   4. When using hand-held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL DADA / 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 

   Fig 2: Checking For Open In Harness Or ECM (THA & EVG)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. OK: Repair or replace harness or connector. 
   2. NG: Go to next step. 

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

   CHECK: 

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

   OK: 

   Temperature value: -40°C (-40°F) 

   Fig 3: Checking For Short In Harness & ECM (THA & E2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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 cover.
   2. Disconnect the E10 connector from the ECM.

      HINT:

      The mass air flow meter connector is disconnected.

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

   CHECK: 

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

   OK: 

   Temperature value: -40°C (-40°F) 

   Fig 4: Checking For Short In Harness & ECM (E10)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. OK: Repair or replace harness or connector. 
   2. NG: Go to next step. 

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