Front Exhaust Pipe And Catalytic Converter: Removal

NOTE: The front exhaust pipe and catalytic converter are only serviced as an assembly; components are not serviced separately.

Raise vehicle squarely on a lift.

Fig 1: Vehicle Support Points
Courtesy of GENERAL MOTORS CORP.

NOTE: Do not apply grease or silicon products to the heated oxygen sensor (H02S-2). Do not alter the wiring in any way. The wires carry air reference to the sensor.
Remove HO2S-2 wiring harness from cradle by pushing up on retaining clip tab.

Fig 2: HO2S-2 Wiring Harness Retaining Clamp
Courtesy of GENERAL MOTORS CORP.
Remove Connector Position Assurance (CPA) device and disconnect HO2S-2 harness connector.

Fig 3: Disconnecting HO2S-2 Harness
Courtesy of GENERAL MOTORS CORP.
Remove HO2S-2 wiring harness from trough in converter heat shield by gently pulling wiring harness from its retaining clips.
NOTE: The HO2S-2 uses a permanently attached pigtail and connector. This pigtail should not be removed from the sensor. Damage or removal of the pigtail or connector will affect proper operation of the sensor.

Fig 4: Removing HO2S-2 Wiring Harness From Trough
Courtesy of GENERAL MOTORS CORP.
Remove HO2S-2 using Gauge Bar Set SA9127E. If necessary, use a liquid penetrate before removing sensor.
Remove (three) front exhaust pipe nuts at manifold.
Loosen front exhaust pipe clamp (15 mm hex) at engine block bracket and slide clamp out of engagement with bracket.
Remove nuts at the outlet of the catalytic converter to intermediate pipe.

Fig 5: Front Exhaust Pipe Clamp And Components
Courtesy of GENERAL MOTORS CORP.
Disengage two rubber isolators from hanger rod on front exhaust pipe and remove pipe from vehicle

Fig 6: Removing Front Exhaust Pipe
Courtesy of GENERAL MOTORS CORP.
Inspect the front exhaust pipe-to-exhaust manifold flange.
Front Exhaust Pipe to Manifold Flange Warpage:
- Service Limit: 0.7 mm (0.028 in.) max.
- Standard: 0.7 mm (0.028 in.) max.