Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection

TROUBLESHOOTING HINTS
If, during engine warm-up, the fast-idling speed is not correct, or black smoke is emitted, the problem is usually a malfunction of the coolant temperature sensor.

INSPECTION




Using Scan Tool




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Harness Inspection





Sensor Inspection
- Remove the engine coolant temperature sensor from the intake manifold.
- With temperature sensing portion of coolant temperature sensor immersed in hot water check resistance.

Temperature versus Resistance:
At 0°C (32°F), Resistance should be 5.8k Ohms
At 20°C (68°), Resistance should be 2.4k Ohms
At 40°C (104°), Resistance should be 1.1k Ohms
At 80°C (176°), Resistance should be 0.3k Ohms

- If the resistance is outside the standard value greatly, replace the sensor.