Inspection Procedure

WARNING: This page is about a different car, the 2007 Toyota Tacoma. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

If other DTCs relating 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 an intelligent tester. 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.

READ VALUE OF INTELLIGENT TESTER (ENGINE COOLANT TEMPERATURE)

Connect an intelligent tester to the DLC3.
Turn the ignition switch ON.
Turn the tester ON.
Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.

Read the value displayed on the tester.

Standard:

Between 80°C and 97°C (176°F and 207°F) with warm engine.

Result

RESULT REFERENCE

Temperature Displayed	Proceed To
-40°C (-40°F)	A
140°C (284°F) or higher	B
Between 80°C and 97°C (176°F and 207°F)	C

HINT:

If there is an open circuit, the intelligent tester indicates -40°C (-40°F).
If there is a short circuit, the intelligent tester indicates 140°C(284°F) or higher.

B: Go to step 4

C : CHECK FOR INTERMITTENT PROBLEMS

A: Go to Next Step

READ VALUE OF INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)
1. Disconnect the E2 Engine Coolant Temperature (ECT) sensor connector.
2. Connect terminals 1 and 2 of the ECT sensor connector on the wire harness side.
3. Connect an intelligent tester to the DLC3.
4. Turn the ignition switch ON.
5. Turn the tester ON.
6. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
7. Read the value displayed on the tester.
  Standard:
  
  140°C (284°F) or higher
8. Reconnect the ECT sensor connector.
OK : CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG: Go to Next Step
READ VALUE OF INTELLIGENT TESTER (CHECK FOR OPEN IN ECM)
1. Disconnect the E2 ECT sensor connector.
2. Connect terminals THW and E2 of the E4 ECM connector.
  HINT:
  
  Before checking, do visual and contact pressure checks on the ECM connector.
3. Connect an intelligent tester to the DLC3.
4. Turn the ignition switch ON.
5. Turn the tester ON.
6. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
7. Read the value displayed on the tester.
  Standard:
  
  140°C (284°F) or higher
8. Reconnect the ECT sensor connector.
OK : REPAIR OR REPLACE HARNESS OR CONNECTOR

NG: CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM
READ VALUE OF INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)
1. Disconnect the E2 ECT sensor connector.
2. Connect an intelligent tester to the DLC3.
3. Turn the ignition switch ON.
4. Turn the tester ON.
5. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
6. Read the value displayed on the tester.
  Standard:
  
  -40°C (-40°F)
7. Reconnect the ECT sensor connector.
  
  Fig 3: ECT Sensor Circuit
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
OK : REPLACE ENGINE COOLANT TEMPERATURE SENSOR

NG: Go to Next Step
READ VALUE OF INTELLIGENT TESTER (CHECK FOR SHORT IN ECM)
1. Disconnect the E4 ECM connector.
2. Connect an intelligent tester to the DLC3.
3. Turn the ignition switch ON.
4. Turn the tester ON.
5. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / COOLANT TEMP.
6. Read the value displayed on the tester.
  Standard:
  
  -40°C (-40°F)
7. Reconnect the ECM connector.
OK : REPAIR OR REPLACE HARNESS OR CONNECTOR

NG: REPLACE ECM