This procedure covers the removal and replacement of the direct-fit catalytic converter on a 2016-2024 Hyundai Tucson with the 2.5L I4 AWD engine, including oxygen sensor handling and exhaust system reassembly.

Warnings

Tools required

Parts

• Direct-fit catalytic converter assembly × 1 — OEM or 49-state/CARB compliant aftermarket
• Exhaust flange gasket (front) × 1 — Use OEM specification
• Exhaust flange gasket (rear) × 1 — Use OEM specification
• Oxygen sensor (if damaged) × 1 — Use OEM specification

Preparation

1. Ensure engine and exhaust system are completely cool to the touch
2. Park vehicle on level surface and engage parking brake
3. Lift front of vehicle and secure on jack stands at manufacturer lift points
4. Spray all exhaust flange bolts, oxygen sensor threads, and hanger bolts with penetrating oil and allow 15-30 minutes to soak
5. Disconnect negative battery terminal to clear oxygen sensor codes during replacement

Procedure

1. 1

   Remove heat shields
   Locate and remove the heat shields covering the catalytic converter. There are typically 2-3 shields secured with 10mm bolts. Remove all heat shield bolts and carefully pull shields away from the exhaust system. Inspect shields for damage and set aside for reinstallation.
   Torque spec

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

   Disconnect upstream oxygen sensor
   Locate the upstream oxygen sensor (before the catalytic converter). Disconnect the electrical connector by pressing the release tab and pulling apart. Using a 22mm oxygen sensor socket, carefully unthread the sensor in a counterclockwise direction. Inspect sensor condition; if threads are damaged or sensor is older than 100k miles, replace it.
   ⚠Do not use excessive force on oxygen sensor. If sensor will not turn after penetrating oil treatment, apply heat carefully to bung area only, keeping sensor element cool.
   Torque spec

   O2 Sensor45 Nm (33 lb-ft)
3. 3

   Disconnect downstream oxygen sensor
   Locate the downstream oxygen sensor (after the catalytic converter). Disconnect the electrical connector. Using the 22mm oxygen sensor socket, remove the sensor and inspect its condition. Keep sensors organized by position if reusing.
   Torque spec

   O2 Sensor45 Nm (33 lb-ft)
4. 4

   Remove front exhaust flange connection
   Locate the front flange connection between the exhaust manifold/turbo downpipe and the catalytic converter inlet. Remove the two or three flange bolts (typically 14mm). Support the catalytic converter with one hand or a suitable support to prevent it from falling when disconnected. Separate the flange connection and remove the old gasket.
   ⚠Support the catalytic converter before removing final bolt to prevent injury from falling component.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
5. 5

   Remove rear exhaust flange connection
   Locate the rear flange connection between the catalytic converter outlet and the intermediate pipe or resonator. Remove the flange bolts while continuing to support the catalytic converter assembly. Carefully separate the flange connection and remove the old gasket.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
6. 6

   Release exhaust hangers
   Identify the rubber exhaust hangers supporting the catalytic converter section. Using an exhaust hanger tool or flat pry bar, carefully work the hanger loops off their mounting brackets. Work methodically to avoid tearing the rubber hangers. Lower the old catalytic converter from the vehicle.
7. 7

   Clean mating surfaces
   Using a wire brush, thoroughly clean both flange mating surfaces on the exhaust manifold/downpipe and intermediate pipe. Remove all old gasket material, carbon deposits, and corrosion. Clean the oxygen sensor bungs in the new catalytic converter to ensure they are free of debris.
8. 8

   Install new catalytic converter
   Position the new catalytic converter assembly into place, aligning it with the front and rear exhaust sections. Install the rubber hanger loops onto their mounting brackets. Ensure the converter is properly oriented with oxygen sensor bungs accessible and heat shield mounting points aligned.
9. 9

   Connect front flange with new gasket
   Install a new front flange gasket between the exhaust manifold/downpipe and catalytic converter inlet. Apply anti-seize compound to the flange bolt threads. Insert and hand-thread all flange bolts, then tighten in a cross-pattern to the specified torque value.
   ℹ️Tighten flange bolts in multiple passes using a cross-pattern to ensure even gasket compression and prevent leaks.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
10. 10

    Connect rear flange with new gasket
    Install a new rear flange gasket between the catalytic converter outlet and intermediate pipe. Apply anti-seize compound to the flange bolt threads. Insert and hand-thread all flange bolts, then tighten in a cross-pattern to the specified torque value.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
11. 11

    Install upstream oxygen sensor
    Apply a thin coat of anti-seize compound to the threads of the upstream oxygen sensor only, keeping compound away from the sensor element. Thread the sensor into the catalytic converter bung by hand, then tighten to specified torque using the 22mm oxygen sensor socket. Reconnect the electrical connector ensuring it clicks securely.
    ⚠Never apply anti-seize to oxygen sensor element or allow contamination. Apply only to threads.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)
12. 12

    Install downstream oxygen sensor
    Apply anti-seize to the threads of the downstream oxygen sensor. Install and torque the sensor to specification, then reconnect its electrical connector. Route oxygen sensor wiring to avoid contact with hot exhaust components or moving parts.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)
13. 13

    Reinstall heat shields
    Position heat shields over the catalytic converter, aligning all mounting holes. Install heat shield bolts and tighten to specification. Ensure shields do not contact any moving components and have proper clearance.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

Reassembly

1. Reconnect negative battery terminal
2. Lower vehicle from jack stands
3. Visually inspect all connections and ensure no tools or parts were left in the engine bay or under the vehicle

Verification

• Start the engine and listen for exhaust leaks at both flange connections. A hissing sound indicates a leak requiring re-torquing or gasket replacement
• Allow engine to reach operating temperature and verify no unusual smells or smoke from exhaust system
• Check that oxygen sensor wiring is properly routed and not contacting exhaust components
• Perform a test drive and verify proper engine performance with no check engine light illumination
• Use an OBD-II scanner to verify oxygen sensor readiness monitors complete properly (may require 50-100 miles of varied driving)
• After 50-100 miles, re-check flange bolt torque and retighten if necessary

More procedures for this vehicle