Engine Coolant Temperature Sensor

ECT sensor is a negative temperature coefficient sensor. Sensor resistance decreases as coolant temperature increases. Coolant temperature information is used by the ECM as a correction factor for the following:

• Cold start enrichment.
• Correction to injection and ignition timing for cold engine.
• Idle speed control.
• Deceleration fuel shut-off.

ECT sensor also is used to activate certain systems at a predetermined temperature such as:

• Heated oxygen sensor control.
• Knock sensor control.