Inspection Procedure

HINT:

• If DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
• Read freeze frame data using a hand-held tester or OBD II scan tool. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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 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 to ON and turn the hand-held tester or the OBD II scan tool ON.
   3. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.

   CHECK: 

   Read the value.

   RESULT: 

   ENGINE COOLANT TEMPERATURE SPECIFICATION TABLE
   
   

   Temperature Display	Proceed To
   -40°C (-40°F)	A
   140°C (284°F) or more	B
   OK (Same as actual engine coolant temperature)	C

   HINT:

   • If there is an open circuit, the hand-held tester or OBD II scan tool indicates -40°C (-40°F).
   • If there is a short circuit, the hand-held tester or OBD II scan tool 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 engine coolant temperature sensor connector.
   2. Connect the sensor wire harness terminals.
   3. Turn the ignition switch to ON.
   4. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.

   CHECK: 

   Read the value.

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

   Fig 1: Checking For Open In Harness Or ECM

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • OK: Confirm good connection to sensor. If OK, replace engine coolant temperature sensor. 
   • NG: Go to next step. 
3. Check for open in harness or ECM. 

   PREPARATION: 

   1. Disconnect the engine coolant temperature sensor connector.
   2. Connect terminals THW and E2 of the ECM connector.

      HINT:

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

   3. Turn the ignition switch to ON.
   4. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.

   CHECK: 

   Read the value.

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

   Fig 2: Checking For Open In Harness Or ECM

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • OK: Repair or replace harness or connector. 
   • NG: Confirm good connection to ECM. If OK, replace ECM (See  ENGINE CONTROL MODULE (ECM)  ). 
4. Check for short in harness and ECM. 

   PREPARATION: 

   1. Disconnect the engine coolant temperature sensor connector.
   2. Turn the ignition switch to ON.
   3. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.

   CHECK: 

   Read the value.

   OK: Temperature value: -40°C (-40°F) 

   Fig 3: Checking For Short In Harness And ECM

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • OK: Replace engine coolant temperature sensor. 
   • NG: Go to next step. 
5. Check for short in harness or ECM. 

   PREPARATION: 

   1. Disconnect the ECM connector.
   2. Turn the ignition switch to ON.
   3. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / COOLANT TEMP.

   CHECK: 

   Read the value.

   OK: Temperature value: -40°C (-40°F) 

   Fig 4: Checking For Short In Harness Or ECM

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • OK: Repair or replace harness or connector. 
   • NG: Replace ECM (See  ENGINE CONTROL MODULE (ECM)  ).