This procedure addresses a common misunderstanding: the 2016-2024 Hyundai Tucson with 2.5L I4 engine uses an electronic transmission with no physical kickdown cable. This guide explains the electronic throttle position system and troubleshooting for transmission performance issues.

Warnings

Tools required

Parts

• Throttle Position Sensor (if faulty) × 1 — Use OEM specification
• Transmission range sensor (if faulty) × 1 — Use OEM specification
• Electrical connector dielectric grease × 1 — Generic automotive grade

Preparation

1. Verify the customer concern is actually related to transmission shift quality or delayed downshifts, not a cable issue
2. Allow engine to cool completely if vehicle was recently driven
3. Park vehicle on level ground and engage parking brake
4. Disconnect negative battery terminal and wait 3 minutes to clear adaptive transmission learning
5. Locate throttle position sensor on throttle body and transmission range sensor on transmission case

Procedure

1. 1

   Scan for diagnostic trouble codes
   Connect OBD-II scanner to diagnostic port under driver side dash. Scan for powertrain codes, particularly P0121-P0124 (throttle position sensor), P0705-P0709 (transmission range sensor), and P0725-P0731 (transmission performance codes). Record all codes and freeze frame data before clearing.
2. 2

   Inspect throttle position sensor connections
   Open hood and locate throttle body on driver side of engine. Inspect the throttle position sensor electrical connector for corrosion, loose pins, or damage. Disconnect connector and examine both male and female terminals. Clean with electrical contact cleaner if corrosion is present.
   ⚠Do not force connector tabs as they are fragile and easily broken. Press release tab fully before pulling.
3. 3

   Test throttle position sensor voltage
   With ignition on but engine off, backprobe the throttle position sensor connector. Verify 5V reference voltage on appropriate pin. Monitor signal voltage while slowly opening throttle plate by hand. Voltage should sweep smoothly from approximately 0.5V to 4.5V without dropouts or erratic readings. Compare to factory specifications in service manual.
4. 4

   Inspect transmission range sensor
   Locate transmission range sensor on driver side of transmission case near shift linkage. Inspect electrical connector for damage, corrosion, or oil contamination. Check that shift linkage moves freely and is properly adjusted. Connector should be clean and fully seated with locking tab engaged.
   ℹ️Oil contamination on this connector indicates a transmission case leak that must be addressed separately.
5. 5

   Test transmission range sensor operation
   With ignition on and scanner connected, monitor transmission range sensor data while cycling shifter through all positions (P-R-N-D-S-L if equipped). Each position should register correctly on scanner without delay or incorrect readings. If readings are incorrect or erratic, sensor or wiring is faulty.
6. 6

   Check transmission fluid level and condition
   Start engine and bring to normal operating temperature. With engine running and transmission in Park on level ground, remove transmission dipstick (located near firewall on passenger side). Wipe clean, reinsert fully, remove and check level in HOT range. Fluid should be bright red and not smell burned. Dark or burnt-smelling fluid indicates internal transmission issues.
   ⚠Transmission fluid will be hot. Use caution when checking level to avoid burns from fluid or nearby exhaust components.
7. 7

   Perform transmission adaptation reset
   Using advanced scanner functions, access TCM (Transmission Control Module) and perform adaptation reset procedure. This clears learned shift points and forces transmission to relearn optimal shift strategy. After reset, test drive vehicle through multiple acceleration and deceleration cycles to allow relearning.
8. 8

   Replace faulty sensors if identified
   If testing revealed faulty throttle position sensor, remove sensor mounting bolts and replace sensor as a complete throttle body assembly (TPS is not serviced separately on this engine). If transmission range sensor is faulty, remove mounting bolts and replace sensor, ensuring proper alignment of manual shaft position.
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)

Reassembly

1. Apply small amount of dielectric grease to all electrical connectors before reconnecting
2. Ensure all connectors are fully seated with locking tabs engaged
3. Reconnect negative battery terminal and torque to specification
4. Clear all diagnostic codes after confirming repairs

Verification

• Start engine and verify no new diagnostic codes are present
• With engine at operating temperature, verify smooth idle and responsive throttle
• Test drive vehicle and verify transmission shifts smoothly through all gears during light, moderate, and heavy acceleration
• Verify transmission downshifts appropriately when throttle is applied during highway speeds (kickdown function)
• Confirm shift quality is firm but not harsh, and timing is appropriate for driving conditions
• Re-scan for codes after test drive to ensure no faults have returned

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