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.
2009 Hummer H3 Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Removal Procedure
- Partially drain the engine coolant below the level of the engine coolant temperature (ECT) sensor. Refer to Cooling System Draining and Filling (Static Fill) or Cooling System Draining and Filling (Vac-N-Fill) .
- Disconnect the ECT sensor electrical connector (2) from the following:
- The engine wiring harness
- The camshaft cover (1)
- Using the J 45861 (4) carefully remove the ECT sensor (3) from the cylinder head (5). See Special Tools .
CAUTION:
Use care when handling the coolant sensor. Damage to the coolant sensor will affect the operation of the fuel control system.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.