Removal Procedure

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Raise and suitably support the vehicle. Refer to LIFTING AND JACKING THE VEHICLE in General Information.
Remove the muffler. Refer to MUFFLER REPLACEMENT (4.8L AND 5.3L ENGINES) or MUFFLER REPLACEMENT (6.0L AND 8.1L ENGINES) .
Disconnect the connector position assurance (CPA) retainers.
Disconnect the oxygen sensor electrical connectors (1, 2).

Fig 1: Removing Oxygen Sensor Electrical Connectors

Courtesy of GENERAL MOTORS CORP.

Remove the left exhaust manifold pipe nuts.

Fig 2: Removing Left Exhaust Manifold Pipe Nuts

Courtesy of GENERAL MOTORS CORP.

Remove the catalytic converter.
Slide the catalytic converter hanger out of the exhaust pipe hanger bracket.

Fig 3: Removing Catalytic Converter Hanger Out Of Exhaust Pipe Hanger Bracket

Courtesy of GENERAL MOTORS CORP.

Remove the oxygen sensors if the catalytic converter is to be replaced.

Fig 4: Removing Catalytic Converter Oxygen Sensors

Courtesy of GENERAL MOTORS CORP.