2002 Pt Cruiser Repair Manual - Get an Instant Estimate. Know the cost of your car repair -- it's fast and free. Over 600,000 car repair estimates provided since 2012. Just fill out the form and get your estimate immediately.. DIAGNOSING PROBLEMS RELATED TO THE COOLANT TEMPERATURE SENSOR by Mark Davidson. The Engine Coolant Temperature Sensor (“ECT” for short) is an analog sensor which, as it’s name says, measures the temperature of the coolant and feeds this data to the on-board computer..