Catalytic Converter - California

Replace the catalytic converters on a 2011-2014 Ford F-150 3.5L EcoBoost with California emissions-compliant units, including oxygen sensor removal and reinstallation.

Warnings

Tools required

Parts

• California-compliant catalytic converter assembly (passenger side) × 1 — CARB-certified replacement for 3.5L EcoBoost
• California-compliant catalytic converter assembly (driver side) × 1 — CARB-certified replacement for 3.5L EcoBoost
• Exhaust flange gasket set × 1 — Use OEM specification
• Exhaust manifold to catalytic converter gaskets × 2 — Use OEM specification

Preparation

1. Ensure engine and exhaust system are completely cold
2. Raise vehicle on level surface and support securely with jack stands rated for vehicle weight
3. Spray all exhaust flange bolts, hanger bolts, and oxygen sensor threads with penetrating oil
4. Disconnect negative battery cable to prevent oxygen sensor codes during disconnection
5. Remove plastic engine undershield if equipped for better access

Procedure

1. 1

   Remove heat shields
   Remove the heat shields covering both catalytic converter assemblies. The shields are secured with multiple bolts. Keep track of bolt locations as some may be different lengths.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
2. 2

   Disconnect oxygen sensors
   Locate the oxygen sensors on both catalytic converter assemblies (upstream and downstream on each side). Disconnect the electrical connectors by pressing the release tabs. Use an oxygen sensor socket or 22mm wrench to carefully unthread each sensor. Turn counterclockwise and avoid binding the threads. Note the position of each sensor for correct reinstallation.
   ⚠Do not allow oxygen sensors to hang by their wires. Support them to prevent wire damage.
3. 3

   Remove passenger side catalytic converter
   Starting with the passenger side, remove the flange bolts connecting the catalytic converter to the exhaust manifold (upstream connection). Then remove the flange bolts connecting to the mid-pipe (downstream connection). Support the catalytic converter assembly as you remove the final bolts. Remove the hanger bolts securing any exhaust hangers supporting this section. Carefully lower the catalytic converter assembly from the vehicle.
   ⚠Exhaust components are heavy and awkward. Have a helper support the assembly or use a transmission jack to prevent dropping.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)

   Hanger Bolts23 Nm (17 lb-ft)
4. 4

   Remove driver side catalytic converter
   Repeat the removal process for the driver side catalytic converter assembly. Remove upstream flange bolts at the exhaust manifold connection, downstream flange bolts at the mid-pipe connection, and any hanger bolts. Support and carefully lower the assembly from the vehicle.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)

   Hanger Bolts23 Nm (17 lb-ft)
5. 5

   Clean mounting surfaces
   Use a wire brush to thoroughly clean all exhaust flange mating surfaces on the exhaust manifolds and mid-pipes. Remove all old gasket material, carbon deposits, and corrosion. Clean the oxygen sensor ports in the new catalytic converters to ensure they are free of debris.
   ℹ️Proper surface preparation ensures leak-free connections and prevents future exhaust leaks.
6. 6

   Install new passenger side catalytic converter
   Position new exhaust manifold gasket on the upstream flange. Apply anti-seize to the threads of the flange bolts (not the bolt heads). Lift the new California-compliant passenger side catalytic converter into position. Start all upstream and downstream flange bolts by hand to ensure proper alignment. Do not fully tighten yet. Install hanger bolts to support the assembly.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)

   Hanger Bolts23 Nm (17 lb-ft)
7. 7

   Install new driver side catalytic converter
   Position new exhaust manifold gasket on the upstream flange. Apply anti-seize to flange bolt threads. Lift the new California-compliant driver side catalytic converter into position. Start all upstream and downstream flange bolts by hand. Install hanger bolts to support the assembly.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)

   Hanger Bolts23 Nm (17 lb-ft)
8. 8

   Torque upstream exhaust connections
   Beginning with the passenger side, torque the exhaust manifold to catalytic converter flange bolts in a crisscross pattern. Repeat for the driver side upstream connection. Ensure anti-seize was applied to bolt threads.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
9. 9

   Torque downstream exhaust connections
   Torque the catalytic converter to mid-pipe flange bolts on both sides in a crisscross pattern. Then torque all hanger bolts to specification.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)

   Hanger Bolts23 Nm (17 lb-ft)
10. 10

    Install oxygen sensors
    Apply a thin coat of anti-seize compound to the threads of each oxygen sensor only (keep anti-seize away from the sensor tip). Thread each sensor into its correct port by hand first to ensure proper thread engagement. Use the oxygen sensor socket to tighten to specification. Do not over-torque as this can damage the sensor or threads.
    ⚠Never apply anti-seize to the oxygen sensor tip or allow contamination of the sensing element.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)
11. 11

    Reconnect oxygen sensor connectors
    Reconnect all oxygen sensor electrical connectors, ensuring each clicks securely into place. Route wiring away from hot exhaust components and sharp edges. Verify no wires are pinched or stretched.
    ℹ️Ensure correct oxygen sensor connections. Swapped sensors will cause incorrect readings and check engine lights.
12. 12

    Reinstall heat shields
    Position heat shields over both catalytic converter assemblies. Install and torque all heat shield bolts to specification. Ensure shields are properly seated and not contacting exhaust pipes.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

Reassembly

1. Reinstall plastic engine undershield if removed
2. Reconnect negative battery cable
3. Lower vehicle from jack stands

Verification

• Start engine and allow to reach operating temperature while monitoring for exhaust leaks at all flange connections
• Listen for unusual exhaust sounds, ticking, or hissing that would indicate leaks
• Use scan tool to verify all oxygen sensors are reading properly and no fault codes are present
• Check that heat shields are not rattling or contacting exhaust components
• Verify California CARB Executive Order number is visible on new catalytic converters for compliance documentation

More procedures for this vehicle