Checking Engine Coolant Temperature Sensor

NOTE: The following procedure assumes that the cooling system thermostat is functioning properly. Test works best if performed on a totally cold engine (cold soak). For connector identification, see CONNECTOR IDENTIFICATION . For component location, see COMPONENT LOCATIONS . For circuit identification and wiring diagram, see WIRING DIAGRAMS article. After each repair procedure has been completed, reconnect all components.

Turn ignition on. With DRBIII(R), monitor Engine Coolant Temperature (ECT) sensor value. Start the engine. Does the ECT reach 180°F (82°C), and was it a smooth transition? If yes, Engine Coolant Temperature sensor is operating normally. Perform POWERTRAIN VERIFICATION TEST VER-2 under VERIFICATION TESTS. If no, replace Engine Coolant Temperature sensor. Perform POWERTRAIN VERIFICATION TEST VER-2 under VERIFICATION TESTS.