Engine Coolant Temperature (ECT) Switch
WARNING: This page is about a different car, the 2003 Toyota Prius and 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
- Drain engine coolant. Remove ECT switch. See COMPONENT LOCATIONS . Place ECT switch thermal sensor into a water bath.
- Using an ohmmeter, check that there is no continuity between ECT switch terminals when coolant temperature is more than 212°F (100°C). If continuity exists, replace ECT switch.
- Cool water and check that there is continuity when coolant temperature is less than 196°F (91°C). If there is no continuity, replace ECT switch. Reinstall switch using new O-ring. Install converter and inverter assembly. Fill with engine coolant.