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.
2000 Pontiac Firefly (CANADA) L4-1.3LFACTORY OEM SERVICE PROCEDURE
Engine Coolant Temperature Sensor Replacement General
Removal Procedure
Caution: Refer to Battery Disconnect Caution in Service Precautions.
1. Disconnect the negative battery cable.
2. Drain the engine cooling system to below the level of the thermostat. Refer to Draining and Filling Cooling System in Cooling System.
3. Remove the ECT sensor electrical connector (3).
4. Remove the ECT sensor from the thermostat housing (2).
Installation Procedure
1. Install the ECT sensor to the thermostat housing (2).
2. Install the ECT sensor electrical connector (3).
3. Refill the engine cooling system. Refer to Draining and Filling Cooling System in Cooling System.
4. Connect the negative battery cable.
Caution: Refer to Battery Disconnect Caution in Service Precautions.
1. Disconnect the negative battery cable.
2. Drain the engine cooling system to below the level of the thermostat. Refer to Draining and Filling Cooling System in Cooling System.
3. Remove the ECT sensor electrical connector (3).
4. Remove the ECT sensor from the thermostat housing (2).
Installation Procedure
1. Install the ECT sensor to the thermostat housing (2).
2. Install the ECT sensor electrical connector (3).
3. Refill the engine cooling system. Refer to Draining and Filling Cooling System in Cooling System.
4. Connect the negative battery cable.
Factory Service Tools
Use the Manual With the Right Hardware
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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.