This procedure covers the replacement of the input speed sensor on the 8-speed automatic transmission of a 2016-2024 Hyundai Tucson with the 2.5L I4 engine and AWD.

Warnings

Tools required

Parts

• Transmission input speed sensor × 1 — Use OEM specification
• Sensor O-ring seal × 1 — Usually included with sensor

Fluids

• Hyundai SP-IV-M ATF — 0.5 qt

Preparation

1. Ensure transmission is cool to the touch
2. Raise vehicle on lift or securely support on jack stands at all four corners
3. Remove driver's side front wheel for improved access (optional but recommended)
4. Remove driver's side front splash shield/fender liner if installed
5. Locate the input speed sensor on the driver's side of the transmission bellhousing, approximately mid-height on the case

Procedure

1. 1

   Disconnect electrical connector
   Press down on the locking tab of the electrical connector attached to the input speed sensor and carefully pull the connector straight away from the sensor. Do not pull on the wires themselves. Inspect the connector for corrosion or damage.
2. 2

   Position drain pan
   Place a small drain pan or container directly beneath the input speed sensor location. Expect approximately 100-200ml of ATF to drain when the sensor is removed.
3. 3

   Remove sensor mounting bolt
   Using a 10mm socket with extension, remove the single bolt securing the input speed sensor to the transmission case. Keep the bolt in a safe location for reinstallation.
4. 4

   Extract sensor from case
   Carefully pull the input speed sensor straight out from the transmission case. Use a slight twisting motion if necessary to break the O-ring seal, but do not pry against the transmission case. Allow ATF to drain into the pan.
   ⚠Do not damage the sensor bore in the transmission case, as this may cause leaks
5. 5

   Clean sensor bore
   Using shop towels and optionally a wire brush or contact cleaner, clean the sensor mounting surface on the transmission case and the sensor bore opening. Remove any debris, old gasket material, or metal particles. Inspect the bore for damage or wear.
6. 6

   Inspect old sensor
   Examine the removed sensor for metal particles on the magnetic tip, damaged connector pins, or physical damage to the sensor body. Check the O-ring for cuts, hardening, or deformation. This can provide diagnostic information about transmission condition.
7. 7

   Prepare new sensor
   Remove the new input speed sensor from packaging. Verify it matches the old sensor in physical appearance and connector type. Install the new O-ring seal onto the sensor body if not pre-installed. Lightly lubricate the O-ring with clean ATF to ease installation.
8. 8

   Install new sensor
   Carefully insert the new input speed sensor into the transmission case bore, ensuring proper alignment. Push the sensor in until it is fully seated against the mounting flange. The sensor should slide in smoothly without excessive force.
   ⚠Ensure the O-ring does not roll or pinch during installation as this will cause ATF leaks
9. 9

   Install and torque sensor bolt
   Install the sensor mounting bolt and hand-tighten. Using a torque wrench, tighten the bolt to specification in a single smooth motion. Do not overtighten as this can damage the sensor housing or transmission case threads.
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)
10. 10

    Reconnect electrical connector
    Push the electrical connector onto the new sensor until you hear or feel a distinct click, indicating the locking tab has engaged. Gently tug on the connector to verify it is secured properly.
11. 11

    Check ATF level
    Start the engine and allow it to reach operating temperature. With the engine running and transmission in Park on level ground, check the ATF level using the dipstick or fill plug (depending on model year). Add Hyundai SP-IV-M ATF as needed to compensate for fluid lost during sensor replacement. Typical loss is 0.25-0.5 quarts.

Reassembly

1. Reinstall the driver's side front splash shield/fender liner if removed
2. Reinstall the driver's side front wheel if removed and torque lug nuts to specification
3. Lower the vehicle to the ground

Verification

• Start the engine and verify no ATF leaks around the input speed sensor mounting area
• Using a diagnostic scan tool, verify the input speed sensor is providing a signal and there are no DTCs related to the sensor
• Test drive the vehicle and confirm smooth shifting through all gears
• Check for proper speedometer operation
• Re-check ATF level after test drive and top off if necessary
• Verify no warning lights are illuminated on the instrument cluster

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