LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Hummer >> 2009 >> H2 4D Utility Pickup >> Repair and Diagnosis >> Engine Mechanical >> Exhaust System >> Repair Instructions >> Catalytic Converter Replacement >> Installation Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Installation Procedure

    Fig 1: Identifying Catalytic Converter To Exhaust Manifold Nuts & Exhaust Seals
    GM1708626Courtesy of GENERAL MOTORS CORP.
  1. Install NEW exhaust manifold seals (2 and 3).
  2. Install the catalytic converter pipe to the exhaust manifolds.
  3. CAUTION: Refer to Fastener Caution .
  4. Install the catalytic converter pipe to exhaust manifold nuts (1) and tighten to 50 N.m (37 lb ft).
  5. Fig 2: Identifying Band Clamp Bolt
    GM1936687Courtesy of GENERAL MOTORS CORP.
  6. Position the three way converter to the muffler assembly and tighten the clamp bolt (1) to 44 N.m(32 lb ft).
  7. Install the transmission crossmember. Refer to Crossmember Replacement (Lower Control Arm) .
  8. IMPORTANT: A special anti-seize compound is used on the HO2S threads. The compound consists of liquid graphite and glass beads. The graphite tends to burn away, but the glass beads remain, making the sensor easier to remove. New, or service replacement sensors already have the compound applied to the threads. If the sensor is removed from as exhaust component and if for any reason the sensor is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.
    Fig 3: Identifying Catalytic Converter Assembly HO2S's
    GM1704008Courtesy of GENERAL MOTORS CORP.
  9. If replacing the three way catalytic converter Install the heated oxygen (HO2S) sensors (1 - 5) otherwise Connect the heated oxygen (HO2S) sensors harness connectors. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 , Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 , Heated Oxygen Sensor Replacement - Bank 2 Sensor 1 and Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 .
  10. Lower the vehicle.
  11. Inspect for exhaust leaks.