9-5 (9600) L4-2.3L Turbo (2007)
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Coolant Temperature Sensor/Switch (For Computer): Description and Operation
Coolant Temperature Sensor
Diagram
The temperature sensor is located on the left-hand end of the cylinder head and is in contact with the engine coolant. The sensor is NTC type.
The control module measures the engine coolant temperature by supplying the sensor with 5V through and integrated 1.0 kohm resistor from pin 39. The
sensor is grounded via control module pin 22. The voltage across the resistor in the control module is proportional to the engine coolant temperature.
Engine coolant temperature is used to:
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calculate the injection duration for pre-injection
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calculate the injection duration while the starter motor is cranking
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calculate after-start enrichment.
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determine when closed loop should be engaged
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correct idling speed.
Diagnostics
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If the sensor voltage is too low, diagnostic trouble code P0117 will be generated.
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If the sensor voltage is too high, diagnostic trouble code P0118 will be generated.
