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.
2008 Hummer H3 L5-3.7LFACTORY OEM SERVICE PROCEDURE
Air Flow Meter/Sensor: Locations
Engine Compartment Components
1 - Engine Control Module (ECM) X1
2 - Engine Control Module (ECM)
3 - Heated Oxygen Sensor (HO2S) 2 (LLR)
4 - Fuse Block - Underhood
5 - Engine Harness
6 - Heated Oxygen Sensor (HO2S) 1 (LLR)
7 - Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor
8 - Engine Control Module (ECM) X3
9 - Engine Control Module (ECM) X2
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.
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