Engine Coolant Temperature (ECT) Switch: Inspection

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: It is not necessary to drain out all the coolant.

Drain engine coolant from radiator .
See CONVERTER & INVERTER ASSEMBLY REMOVAL .
Remove engine coolant temperature switch :
1. Disconnect the connector.
  
  Fig 1: Locating Water Temperature Switch & Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Remove the water temperature switch.
Inspect engine coolant temperature switch continuity :
1. Using an ohmmeter, check the no continuity exists between the terminals when the coolant temperature is above 100°C (212°F).
  
  Fig 2: Testing Engine Coolant Temperature Switch
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  If continuity exists, replace the switch.
2. Using an ohmmeter, check the continuity exists between the terminals when the coolant temperature is below 91°C (196°F).
  If no continuity exists, replace the switch.

NOTE: Lubricate a new "O" ring with soapy water and install them to the switch.

Install engine coolant temperature switch .
Torque: 34 N.m (350 kgf.cm, 25 ft.lbf) .
See INSTALLATION OF CONVERTER & INVERTER .
Fill with engine coolant .