AP Exhaust 770543 Catalytic Converter - Left

Direct-Fit Catalytic Converter for Cadillac CTS and STS

AP Exhaust 770543 is a CARB-compliant direct-fit catalytic converter built for specific left-side Cadillac applications. It is engineered to match OE dimensions and fitment for a cleaner installation on 2008-2011 Cadillac CTS and Cadillac STS models listed below.

The AP Exhaust 8GMXV03.6053 product line focuses on precise fitment and efficient converter construction, using advanced manufacturing methods to help maintain consistent dimensions and reliable installation alignment. This part number, 770543, is built around a ceramic substrate and California emissions compliance requirements.

Key Features

• CARB compliant direct-fit catalytic converter
• Ceramic substrate material
• 2-bolt welded flange inlet
• 2-bolt welded flange outlet with gasket stub
• 1 O2 sensor port
• Inlet gasket included
• Outlet gasket included
• Overall length: 18.5 inches
• Executive Order: D-798-9

Detailed Description

AP Exhaust 770543 is designed for left-side exhaust service on California-emissions Cadillac CTS and Cadillac STS vehicles. The converter uses a ceramic substrate and OE-style direct-fit construction to support proper alignment with the factory exhaust layout. For buyers searching for a 2011 Cadillac CTS left catalytic converter, a 2010 Cadillac STS left catalytic converter, or a 2008 Cadillac CTS California emissions replacement, this part matches the listed applications and configuration.

The AP Exhaust 8GMXV03.6053 line is built with manufacturing controls that help keep converter dimensions consistent from unit to unit. That matters when replacing a catalytic converter on a Cadillac CTS or Cadillac STS, where flange style, sensor port count, and overall length must match the original exhaust routing. This part number, 770543, is listed for California-compliant use only in the applications shown.

Vehicle Fitment

• Fits 2011 Cadillac CTS, left. Direct Fit - California; BGMXV03.6053; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2011 Cadillac STS, left. Direct Fit - California; BGMXV03.6053; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2010 Cadillac CTS, left. Direct Fit - California; AGMXV03.6053; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2010 Cadillac STS, left. Direct Fit - California; AGMXV03.6053; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2009 Cadillac CTS, left. Direct Fit - California; 9GMXV03.9148; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2009 Cadillac CTS, left. Direct Fit - California; 9GMXV03.6053; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2009 Cadillac CTS, left. Direct Fit - California; 9GMXJ03.9148; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2009 Cadillac STS, left. Direct Fit - California; 9GMXV03.6053; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2008 Cadillac CTS, left. Direct Fit - California; 8GMXV03.6053; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2008 Cadillac CTS, left. Direct Fit - California; 8GMXB03.6148; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.
• Fits 2008 Cadillac STS, left. Direct Fit - California; 8GMXV03.6053; ALL; Legal Note: In Compliance with California Emissions Requirements; EO Number: D-798-10.

Common Repair Uses

• Replacing a failed or restricted left-side catalytic converter
• Addressing emissions test failures on California-compliant Cadillac applications
• Restoring exhaust flow after catalyst substrate damage
• Correcting check-engine light conditions related to catalyst efficiency
• Replacing a converter with damaged flanges or sensor-port issues

Installation Notes and Tips

Verify the vehicle year, model, and left-side application before installation. Confirm the inlet and outlet flange style, O2 sensor port location, and overall length against the original converter to ensure proper alignment. Because this unit is listed as a direct-fit California emissions part, it should be matched only to the exact applications shown for Cadillac CTS and Cadillac STS.

AP Exhaust 770543 uses inlet and outlet gaskets as listed in the product attributes, while inlet and outlet hardware are not included. This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

Quality Assurance

AP Exhaust states that its converter manufacturing uses automated workstations, spinner welding equipment, and high-speed production lines to help maintain OE dimensions and consistent fitment. The product is identified with Executive Order D-798-9 and is listed as CARB compliant for the specified California applications.