Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1998ASTRO VAN 2WD V6-4.3L VIN WREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSCOOLANT TEMPERATURE SENSOR/SWITCH (FOR COMPUTER)DESCRIPTION AND OPERATION
1998 Chevrolet Astro Van 2WD V6-4.3L VIN W
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
1998 Chevrolet Astro Van 2WD V6-4.3L VIN WSECTION Description and Operation
Engine Coolant Temperature (ECT) Sensor:
DESCRIPTION
The engine coolant temperature sensor is a thermistor (a resistor which changes value based on temperature) mounted in the engine coolant passage. Low coolant temperature produces a high resistance 100,000 ohms at -40°C (-40°F) while high temperature causes low resistance 70 ohms at 130°C (266°F).
OPERATION
The VCM supplies a 5 volt signal to the engine coolant temperature sensor through a resistor in the VCM and measures the voltage. The voltage will be high when the engine is cold. The voltage will be low when the engine is hot. By measuring the voltage, the VCM calculates the engine coolant temperature. Engine coolant temperature affects most systems the VCM controls.
^ The scan tool displays engine coolant temperature in degrees. After engine start-up, the temperature should rise steadily to about 90°C (194°F) then stabilize when thermostat opens. If the engine has not been run for several hours (overnight), the engine coolant temperature and intake air temperature displays should be close to each other. A fault in the engine coolant sensor circuit should set DTC P0117 or DTC P0118.
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.