GM 19169161
Catalytic Converter

The replacement of rear catalytic converters from 3.5l engines starts by uninstalling the main Muffler assembly. Remove the connector position assurance (CPA) retainer from the system while disconnecting the heated oxygen sensor (HO2S) electrical connector but make sure the permanently attached pigtail stays intact. The heated oxygen sensor wrench (J 39194-B) should be used to detach the ho2s . Start by removing the Catalytic Converter to rear Catalytic Converter nuts, then proceed to the Catalytic Converter bolt and nuts at the Exhaust Manifold, and conclude by taking out the rear Catalytic Converter . Dispose of the old gasket and confirm that the Catalytic Converter-to-exhaust manifold flange shows no more than 0.7 mm (0.028 inch) maximum deformation during inspection. During installation place a new gasket onto the Catalytic Converter studs before installing the rear Catalytic Converter then secure it with the Catalytic Converter bolt and nuts at the Exhaust Manifold using 31 nm of torque (23 ft. Lbs.). Secure the front Catalytic Converter to the rear Catalytic Converter using nuts while twisting them to 31 nm (23 ft. Lbs.). Use the heated oxygen sensor wrench (J 39194-B) to reinstall the ho2s and tighten it to 42 nm (31 ft. Lbs.). Afterward, connect the ho2s electrical connector and install the cpa retainer. Reinstall the Muffler assembly before beginning the engine and checking for exhaust leaks.

Remove the front catalytic converter to rear catalytic converter nuts, and finally the front catalytic converter itself, discarding its gasket as well.