Inspection Procedure

HINT:

If different DTCs that are related to different systems are output simultaneously while terminal E2 is used as a ground terminal, 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.

Connect hand-held tester or OBD II scan tool and read value of engine coolant temperature.
PREPARATION:
1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
2. Turn the ignition switch ON.
3. Push the hand-held tester or OBD II scan tool main switch ON.
4. On the hand-held tester or OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.
CHECK:

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

OK:

Same value as the actual engine coolant temperature.

HINT:
- If there is open circuit, hand-held tester or OBD II scan tool indicates -40°C (-40°F).
- If there is short circuit, hand-held tester or OBD II scan tool indicates 140°C (284°F) or more.
1. NG :
2. -40°C (-40°F) ..... Go to step 2.
3. 140°C (284°F) or more ..... Go to step 4 .
4. OK : Check for intermittent problems (see PRE-CHECK ).
Check for open in harness or ECM.
PREPARATION:
1. Disconnect the ECT sensor connector.
2. Connect terminals 1 and 2 of the ECT sensor wire harness side connector.
3. Connect the hand-held tester or OBD II scan tool to the DLC3.
4. Turn the ignition switch ON.
5. Push the hand-held tester or OBD II scan tool main switch ON.
6. On the hand-held tester or OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.
  
  Fig 1: Checking For Open In Harness Or ECM
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
CHECK:

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

OK:

Temperature value: 140°C (284°F) or more
1. OK : Confirm good connection at sensor. If OK, replace engine coolant temperature sensor.
2. NG : Go to next step.
Check for open in harness or ECM.
PREPARATION:
1. Disconnect the ECT sensor connector.
2. Connect terminals THW and E2 of the ECM connector.
  HINT:
  
  Before checking, perform a visual and contact pressure check for the ECU connector.
3. Connect the hand-held tester or OBD II scan tool to the DLC3.
4. Turn the ignition switch ON.
5. Push the hand-held tester or OBD II scan tool main switch ON.
6. On the hand-held tester or OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.
  
  Fig 2: Checking Open In Harness Or ECM And Locating THW And E2 Connector Terminals Of ECM
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
CHECK:

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

OK:

Temperature value: 140°C (284°F) or more
1. OK : Open in harness between terminals E2 or THW, repair or replace harness.
2. NG : Confirm good connection at ECM. If OK, replace ECM (see COMPONENTS ).
Check for short in harness and ECM.
PREPARATION:
1. Disconnect the ECT sensor connector.
2. Connect the hand-held tester or OBD II scan tool to the DLC3.
3. Turn the ignition switch ON.
4. Push the hand-held tester or OBD II scan tool main switch ON.
5. On the hand-held tester or OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.
  
  Fig 3: Checking For Short In Harness And ECM
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
CHECK:

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

OK:

Temperature value: -40°C (-40°F)
1. OK : Replace ECT sensor.
2. NG : Go to next step.
Check for short in harness or ECM.
PREPARATION:
1. Disconnect the E6 ECM connector.
2. Connect the hand-held tester or OBD II scan tool to the DLC3.
3. Turn the ignition switch ON.
4. Push the hand-held tester or OBD II scan tool main switch ON.
5. On the hand-held tester or OBD II scan tool, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.
  
  Fig 4: Checking For Short In Harness Or ECM And Locating E6 Connector Of ECM
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
CHECK:

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

OK:

Temperature value: -40°C (-40°F)
1. OK : Repair or replace harness and connector.
2. NG : Replace ECM (see COMPONENTS ).