Coolant Temperature Sensor (CTS) What It Does: The coolant temperature sensor is required by the computer for correct engine coolant temperature measurement. Location: The Coolant Temperature Sensor may be located on the engine block, intake manifold, or cylinder head Failure Symptom: Malfunction Indicator Light (MIL) illumination, failed emission test, engine no-start condition, engine hesitation on acceleration, engine cooling fan condition turns on too late or not at all.
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