This procedure covers the removal and replacement of all oxygen sensors (upstream and downstream) on the 2016-2024 Hyundai Tucson 2.5L I4 AWD engine.

Warnings

Tools required

Parts

• Upstream O2 sensor (Bank 1 Sensor 1) × 1 — Use OEM specification
• Downstream O2 sensor (Bank 1 Sensor 2) × 1 — Use OEM specification
• Upstream O2 sensor (Bank 2 Sensor 1) × 1 — Use OEM specification
• Downstream O2 sensor (Bank 2 Sensor 2) × 1 — Use OEM specification

Preparation

1. Ensure engine and exhaust system are completely cold to the touch
2. Park vehicle on level ground and engage parking brake
3. Place wheel chocks behind rear wheels
4. If O2 sensor fault codes are present, note which sensor(s) are indicated before clearing codes
5. Raise and secure front of vehicle on jack stands at manufacturer lift points
6. Remove plastic engine undertray if equipped for better access to sensors

Procedure

1. 1

   Locate all four O2 sensors
   Identify sensor locations: Bank 1 Sensor 1 (upstream) is located in the exhaust manifold before the catalytic converter on the driver side. Bank 1 Sensor 2 (downstream) is located after the catalytic converter on the driver side. Bank 2 Sensor 1 (upstream) is in the exhaust manifold before the catalytic converter on the passenger side. Bank 2 Sensor 2 (downstream) is after the catalytic converter on passenger side. Trace electrical connectors from each sensor.
2. 2

   Disconnect battery negative terminal
   Disconnect the negative battery terminal to prevent electrical faults and ensure safe sensor replacement. Wait 3 minutes for system capacitors to discharge before proceeding.
3. 3

   Disconnect Bank 1 Sensor 1 electrical connector
   Locate the upstream O2 sensor connector on the driver side near the exhaust manifold. Press the release tab and carefully disconnect the electrical connector. If connector is corroded, apply electrical contact cleaner and work gently to avoid breaking clips.
4. 4

   Remove Bank 1 Sensor 1
   Using the O2 sensor socket and ratchet, turn the sensor counterclockwise to remove. If sensor is seized, apply penetrating oil and allow 15 minutes to soak. Do not use excessive force as threads in exhaust manifold can be damaged. Work sensor back and forth gently if stuck.
   ⚠Seized sensors may require additional penetrating oil soaking time. Damaged exhaust manifold threads require professional thread repair.
5. 5

   Remove Bank 1 Sensor 2
   Disconnect electrical connector for the downstream sensor on driver side. Using O2 sensor socket, remove sensor from exhaust pipe after the catalytic converter. This sensor is typically more accessible from underneath the vehicle.
6. 6

   Remove Bank 2 Sensor 1
   Disconnect electrical connector for upstream sensor on passenger side. Access may require working from above or below depending on component packaging. Remove sensor from exhaust manifold using O2 sensor socket.
7. 7

   Remove Bank 2 Sensor 2
   Disconnect electrical connector for downstream sensor on passenger side. Remove sensor from exhaust pipe after catalytic converter. This is the final sensor to be removed.
8. 8

   Clean sensor bung threads
   Using a wire brush, clean the threads in each sensor bung location in the exhaust manifold and pipes. Remove any carbon buildup, debris, or old anti-seize compound. Ensure threads are clean and undamaged.
9. 9

   Prepare new sensors for installation
   Apply a thin coat of anti-seize compound to the threads of each new O2 sensor. Apply only to threads, keeping anti-seize away from the sensor tip and perforations. Ensure each sensor has the correct connector type for its location.
   ⚠️Never apply anti-seize or any lubricant to the sensor tip. Contamination will cause immediate sensor failure and incorrect readings.
10. 10

    Install Bank 1 Sensor 1
    Thread new upstream sensor into driver side exhaust manifold by hand to avoid cross-threading. Once hand-tight, use O2 sensor socket to tighten to specification. Do not over-tighten as this can damage sensor or exhaust manifold threads.
    Torque spec

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

    Install Bank 1 Sensor 2
    Thread new downstream sensor into driver side exhaust pipe after catalytic converter. Hand-tighten first, then torque to specification using O2 sensor socket.
    Torque spec

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

    Install Bank 2 Sensor 1
    Thread new upstream sensor into passenger side exhaust manifold. Hand-tighten first, then torque to specification using O2 sensor socket.
    Torque spec

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

    Install Bank 2 Sensor 2
    Thread new downstream sensor into passenger side exhaust pipe after catalytic converter. Hand-tighten first, then torque to specification using O2 sensor socket.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)
14. 14

    Reconnect all electrical connectors
    Connect each O2 sensor electrical connector, ensuring positive engagement with audible click. Route wiring away from hot exhaust components and moving parts. Verify all four connectors are securely attached.
15. 15

    Reconnect battery and reinstall undertray
    Reconnect negative battery terminal. If removed, reinstall plastic engine undertray. Lower vehicle from jack stands.

Reassembly

1. Ensure all sensor electrical connectors are fully seated and locked
2. Verify sensor wiring is routed away from exhaust heat and moving components
3. Double-check that all four sensors are torqued to specification
4. Reinstall any components removed for access

Verification

• Start engine and verify no exhaust leaks are present at sensor mounting locations
• Allow engine to reach operating temperature and idle for 5 minutes
• Use OBD-II scanner to verify all four O2 sensors are reporting data and no fault codes are present
• Perform test drive to allow sensors to cycle through normal operating conditions
• Re-check for fault codes after test drive - sensors may take several drive cycles to complete readiness monitors
• Verify no unusual exhaust odors or sounds are present

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