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 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 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 and push the hand-held tester or the OBD II scan tool main switch ON.
   3. When using the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL DADA / COOLANT TEMP.

   CHECK: 

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

   OK: 

   1. Same value as the actual engine coolant temperature and temperature displayed on the handheld tester or the OBD II scan tool. 

   RESULT: 

   DISPLAYED TEMPERATURE RESULTS
   
   

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

   HINT:

   • If there is an open circuit, the hand-held tester or the OBD II scan tool indicates -40°C (-40°F).
   • If there is a short circuit, the hand-held tester or the OBD II scan tool 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 engine coolant temp, sensor connector.
   2. Connect the sensor wire harness terminals together.
   3. Turn the ignition switch ON.
   4. When using the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL DADA / COOLANT TEMP.
   Fig 1: Testing Engine Coolant Temperature Sensor Circuits

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   CHECK: 

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

   OK: 

   1. 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. 
3. Check for open in harness or ECM. 

   PREPARATION: 

   1. Remove the ECM cover.
   2. Connect between terminals THW and E2 of the ECM connector.

      HINT:

      Engine coolant temp, sensor connector should be disconnected. Before checking, do a visual and contact pressure check for the ECM connector (See PROCEDURE ).

   3. Turn the ignition switch ON.
   4. When using the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL DADA / COOLANT TEMP.
   Fig 2: Identifying Engine Coolant Sensor Circuits & ECM Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   CHECK: 

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

   OK: 

   1. Temperature value: 140°C (284°F) or more 
   1. OK : Repair or replace harness and connector. 
   2. 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 engine coolant temp, sensor connector.
   2. Turn the ignition switch ON.
   3. When using the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL DADA / COOLANT TEMP.
   Fig 3: Disconnecting Engine Coolant Temperature Sensor

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   CHECK: 

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

   OK: 

   1. Temperature value:-40°C (-40°F) 
   1. OK : Replace engine coolant temperature sensor. 
   2. NG : Go To Next Step. 
5. Check for short in harness or ECM. 

   PREPARATION: 

   1. Remove the ECM cover.
   2. Disconnect the E4 connector of the ECM.

      HINT:

      Engine coolant temp, sensor connector is disconnected.

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

   CHECK: 

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

   OK: 

   1. Temperature value:-40°C (-40°F) 
   Fig 4: Disconnecting ECM E4 Connector

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