2025 Hyundai Tucson DCU Software Update (Service Campaign TDFA)

Symptoms

Owners of certain 2025 Hyundai Tucson (NX4) vehicles may encounter a Data Communication Unit (DCU) software error. This issue stems from the internal timer initialization logic not being properly implemented within the DCU module.

The primary symptom of this software error is the potential for the DCU module to shut down telematics services after one year of operation. This means features like emergency assistance, remote services, and other connected car functionalities could become inoperable.

What Owners Should Know

Hyundai has issued Service Campaign TDFA, documented in Technical Service Bulletin (TSB) 25-01-059H-1, to address the DCU software issue. This bulletin supersedes the previous TSB 25-01-059H and includes additional information for VCI 2 connection and IP settings.

Dealers are mandated to perform this service campaign on all affected 2025 Hyundai Tucson vehicles prior to customer retail delivery. Furthermore, the update must be applied whenever an affected vehicle is brought into the shop for any maintenance or repair.

For the software update process, it is crucial that the vehicle's battery charge is above 11.0 Volts and the diagnostic tablet's battery charge is above 30% to prevent update failure. During the update, technicians are instructed to turn OFF all lamps and accessories, and specifically "do NOT leave head lamp switch in auto mode".

It is also critical that technicians "do NOT disconnect any cables connected to the vehicle or scan tool during the update", "do NOT start the engine during the update", and "do NOT turn OFF the ignition switch during the update". If the update fails, the power connector must be removed from the in-cabin fuse box for at least 5 seconds, or the negative (-) 12V battery terminal disconnected for at least 5 seconds before retrying.

When using a VCI 2 diagnostic tool, technicians are advised to wait for the Wi-Fi Direct connection to establish and "do NOT select Bluetooth Only". Owners should be aware that the VIN/Date/Time/Mileage photo imprint is "NOT required for GDS screenshots" during this procedure.

Repair Procedure Summary

The repair involves a software update to the Data Communication Unit (DCU) module using the Hyundai GDS (Global Diagnostic System). The process begins with ensuring proper battery voltage and turning off all vehicle accessories and lights.

Technicians connect the appropriate diagnostic interface, either a VCI 3 or VCI 2 with an Ethernet Communication Interface (ECI) Kit, to the vehicle's OBD connector and a tablet. Specific IP settings are then configured on the tablet to ensure proper communication.

The ECU update is initially performed in Auto Mode. If the update fails in Auto Mode, it must be performed in Manual Mode using a specific password (2419 for Event 1297, ECU Menu NX4 PE DCU 96510-N9140). After the update is 100% complete, the ignition must be cycled OFF for 10 to 30 seconds to reset the control unit.

Finally, an OTA (Over-the-Air) initialization process is performed, either automatically or manually if needed. Technicians then perform an All Systems Fault Code search and erase any incidental DTC history that may have occurred during the update, followed by starting the engine to confirm proper operation.

Required Tools and Parts

To perform the DCU software update, Hyundai technicians utilize specialized service tools:

• VCI 3: Tool Number G0VHNNN06 (includes 19-Pin Cable G1XDDCA020)
• VCI 2: Tool Number G1XDDMN001
• Ethernet Communication Interface (ECI) Kit: Tool Number G0XDDMN052 (required if using VCI 2)

These tools facilitate the connection between the diagnostic tablet and the vehicle's Data Communication Unit. The causal part associated with this campaign is 96510-N9140, which refers to the DCU module itself.

Owner Action

If you own a 2025 Hyundai Tucson (NX4), your vehicle may be subject to this service campaign. Hyundai is addressing this issue proactively, and dealers are required to perform the update on all affected vehicles before retail delivery or during any service visit.

For customers with active Bluelink Services subscriptions, the software update may be available as an OTA (Over-the-Air) option. You can check the "Vehicle Information" screen via WebDCS or contact your local Hyundai dealership to identify any open campaigns for your vehicle. The operation code for this DCU Software Update is 50D236R0, with an estimated repair time of 0.4 hours.

NHTSA ID: 11025593