🔧 Niro - Oxygen Sensor Replacement (All Sensors)

Your Niro uses oxygen sensors to measure exhaust oxygen so the engine computer can control fuel mixture and monitor the catalytic converter. Replacing both sensors means doing the upstream sensor (before the catalytic converter) and the downstream sensor (after the catalytic converter) and making sure the wiring is routed exactly like factory.

Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours

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⚠️ Safety & Precautions

• ⚠️ Exhaust parts get extremely hot—work only on a fully cool exhaust.
• ⚠️ Your Niro is a plug-in hybrid—do not touch or probe any orange high-voltage wiring or connectors.
• ⚠️ Support the vehicle with jack stands—never rely on a floor jack alone.
• ⚠️ If you disconnect the 12V battery, keep the key/fob away from the car to prevent modules waking up.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Mechanic gloves
• Wheel chocks
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• 3/8" drive ratchet
• 3/8" drive extension set
• Torque wrench (10–100 ft-lbs range)
• Oxygen sensor socket 22mm (specialty)
• Penetrating oil
• Trim clip removal tool
• Flathead screwdriver
• OBD2 scan tool (specialty)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Upstream oxygen sensor (Sensor 1) - Qty: 1
• Downstream oxygen sensor (Sensor 2) - Qty: 1
• High-temperature anti-seize (sensor-safe) - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and chock the rear wheels.
• Let the exhaust cool completely (at least 1 hour after driving).
• If you choose to disconnect power: disconnect the 12V battery negative terminal using a wrench and wait 5 minutes.
• Plan sensor locations: upstream is on the exhaust/catalyst area closer to the engine; downstream is after the catalytic converter under the vehicle.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Raise and secure the vehicle

• Place wheel chocks behind the rear tires.
• Lift the front with a floor jack (rated 3-ton minimum) and set the car on jack stands (rated 3-ton minimum).
• Give the vehicle a firm shake to confirm it’s stable before going underneath.

Step 2: Locate both oxygen sensors

• Use a flashlight from your phone (if needed) and visually find the sensor bungs (threaded holes) on the exhaust.
• Upstream sensor: closer to the engine (before the catalytic converter).
• Downstream sensor: further back (after the catalytic converter).
• Follow the wire to the connector.

Step 3: Unplug the upstream sensor connector

• Spray the sensor threads area with penetrating oil and wait 5–10 minutes.
• Release any wiring clips using a trim clip removal tool or flathead screwdriver.
• Unplug the connector by pressing the lock tab; use a flathead screwdriver gently if the tab is stubborn.

Step 4: Remove the upstream oxygen sensor

• Install the oxygen sensor socket 22mm (specialty) over the sensor wire and onto the sensor hex.
• Use a 3/8" drive ratchet and a 3/8" drive extension set as needed for clearance.
• Turn counterclockwise to remove the sensor.
• If it won’t budge, apply more penetrating oil, wait, and try again—avoid rounding the hex.

Step 5: Install the new upstream oxygen sensor

• Start threading the new sensor by hand to avoid cross-threading.
• If the new sensor threads are not pre-coated, apply a tiny amount of high-temperature anti-seize (sensor-safe) to the threads only (keep it off the sensor tip).
• Tighten with the oxygen sensor socket 22mm (specialty) and torque wrench: Torque to 44 Nm (32 ft-lbs).
• Reconnect the electrical connector until it clicks, then re-secure the harness with the factory clips.

Step 6: Unplug the downstream sensor connector

• Move to the downstream sensor area under the vehicle.
• Release harness clips using a trim clip removal tool.
• Unplug the connector (press the lock tab); use a flathead screwdriver carefully if needed.

Step 7: Remove and install the downstream oxygen sensor

• Spray threads with penetrating oil and wait 5–10 minutes.
• Remove the sensor using the oxygen sensor socket 22mm (specialty) with a 3/8" drive ratchet and 3/8" drive extension set.
• Hand-thread the new sensor first, then tighten with a torque wrench: Torque to 44 Nm (32 ft-lbs).
• Reconnect the connector and re-clip the wiring so it cannot touch the exhaust.

Step 8: Re-check routing and lower the vehicle

• Confirm both connectors are fully seated and locked.
• Confirm the harness is clipped up and away from the exhaust.
• Lower the vehicle using the floor jack (rated 3-ton minimum) and remove the jack stands (rated 3-ton minimum).

Step 9: Clear codes and verify the repair

• Plug in an OBD2 scan tool (specialty) and clear any stored oxygen sensor codes.
• Start the engine and let it idle for a few minutes while you listen for exhaust leaks.
• Re-scan for codes after a short drive.

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✅ After Repair

• Verify no warning lights return after a 10–15 minute mixed drive.
• Use an OBD2 scan tool (specialty) to confirm no pending codes and that O2 sensor readings are active.
• If you disconnected the 12V battery, reset the clock and any saved settings as needed.

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💰 DIY vs Shop Cost

Shop Cost: $350-$750 (parts + labor)

DIY Cost: $140-$420 (parts only)

You Save: $210-$330 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 hours.

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🎯 Ready to get started?

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