Coolant Temperature Sensor / Switch HVAC: Testing and Inspection
ENGINE COOLANT TEMPERATURE (ECT) SWITCHINSPECTION
1. DRAIN ENGINE COOLANT FROM RADIATOR
HINT: It is not necessary to drain out all the coolant.
2. REMOVE ECT SWITCHES
a. Disconnect the connector.
b. Remove the ECT switch.
3. 5S-FE engine:
INSPECT ECT SWITCH CONTINUITY
a. Using an ohmmeter, check that no continuity exists between the terminals when the coolant temperature is above 93°C (199°F).
If continuity exists, replace the switch.
b. Using an ohmmeter, check that continuity exists between the terminals when the coolant temperature is below 83°C (181°F).
If no continuity exists, replace the switch.
4. 1MZ-FE engine:
INSPECT No.1 SWITCH CONTINUITY
a. Using an ohmmeter, check that no continuity exists between the terminals when the coolant temperature is above 98°C (208°F).
If continuity exists, replace the switch.
b. Using an ohmmeter, check that continuity exists between the terminals when the coolant temperature is below 88°C (190°F).
If no continuity exists, replace the switch.
5. 1MZ-FE engine:
INSPECT No.2 SWITCH CONTINUITY
a. Using an ohmmeter, check that no continuity exists between the terminal and switch body when the coolant temperature is above 93°C (199°F).
If continuity exists, replace the switch.
b. Using an ohmmeter, check that continuity exists between the terminals when the coolant temperature is below 83°C (181 °F).
If no continuity exists, replace the switch.
6. INSTALL ECT SWITCHES
a. Install the ECT switch.
HINT: Lubricate a new O-ring with soapy water and install the switch.
b. Connect the connector.