Engine Coolant Temperature (ECT) Sensor

ECT sensor is a negative temperature coefficient sensor. Sensor resistance decreases as coolant temperature increases. Coolant temperature information is used by the MFI 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.

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

• HO2S control
• KS control
• EGR operation.