Engine Coolant Temperature Gauge Sender: Prius

Engine Coolant Temperature (ECT) sender is located on end of cylinder head at flywheel end of engine and contains a Black 2-pin electrical connector with Green and Red wires. Manufacturer states that converter and inverter assembly must be removed for access to ECT sender. The converter and inverter assembly are involved with the high-voltage system used on this vehicle and service procedure should only be performed by authorized dealer.

1. Turn ignition off. Disconnect ECT sender 2-pin connector. Drain cooling system and remove ECT sender. Place probe end of ECT sender and thermometer in a container of water. Connect an ohmmeter between ECT sender terminals.
2. Heat water and note resistance reading. See ENGINE COOLANT TEMPERATURE GAUGE SENDER RESISTANCE  table. If resistance is not as specified, replace ECT sender.