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.
2007 Chevrolet TrailBlazer 4WD L6-4.2LFACTORY OEM SERVICE PROCEDURE
Coolant Temperature Sensor/Switch (For Computer): Service and Repair
Engine Coolant Temperature Sensor Replacement
Removal Procedure
Notice: Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.
1. Turn the engine OFF.
Caution: Refer to Battery Disconnect Caution.
2. Disconnect the negative battery terminal.
3. Drain coolant below the level of the engine coolant temperature (ECT) sensor. Refer to Draining and Filling Cooling System (LL8) Draining and Filling Cooling System (LH6, LS2).
4. Disconnect the ECT sensor electrical connector (1).
5. Carefully remove the ECT sensor (1).
Installation Procedure
Notice: Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.
Notice: Replacement components must be the correct part number for the application. Components requiring the use of the thread locking compound, lubricants, corrosion inhibitors, or sealants are identified in the service procedure. Some replacement components may come with these coatings already applied. Do not use these coatings on components unless specified. These coatings can affect the final torque, which may affect the operation of the component. Use the correct torque specification when installing components in order to avoid damage.
1. If installing the original sensor or a new sensor without sealant, apply thread sealer P/N 12346004 or equivalent.
Notice: Refer to Fastener Notice.
2. Install the ECT sensor.
Tighten the ECT sensor to 16 N.m (12 lb ft).
3. Connect the ECT electrical connector (1).
4. Connect the negative battery terminal.
5. Refill the engine coolant. Refer to Draining and Filling Cooling System (LL8) Draining and Filling Cooling System (LH6, LS2).
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.
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