2025 Hyundai Tucson DCU Software Update (25-01-059H)

Hyundai has issued Service Campaign 25-01-059H (TDFA) to address a potential "DCU software error" in certain 2025 Hyundai Tucson (NX4) vehicles. This issue stems from an internal timer initialization logic that was not properly implemented in the Data Communication Unit (DCU) module. As a result, the DCU module may shut down telematics services after one year of operation.

This bulletin provides instructions for dealers to perform a software update to the DCU module, ensuring continued functionality of telematics services.

Symptoms and Diagnosis

The primary symptom of this issue is the potential for telematics services to shut down after one year of vehicle operation. This occurs due to a "DCU software error" related to the internal timer initialization logic within the Data Communication Unit (DCU) module.

Dealers can identify affected vehicles by accessing the “Vehicle Information” screen via WebDCS to check for open campaigns, specifically Service Campaign 25-01-059H.

Important Warnings for Owners and Technicians

Hyundai has provided critical instructions and warnings regarding this software update:

• Dealers must perform this service campaign on all affected vehicles prior to customer retail delivery and whenever an affected vehicle is in the shop for any maintenance or repair.
• The software update is subject to an Over-the-Air (OTA) option and may be completed by customers with active Bluelink Services subscriptions.
• You must initially perform the GDS ECU update in Auto Mode. If the ECU update starts but then fails in Auto Mode, perform the update in Manual Mode to recover.
• Ensure the vehicle's battery charge is above 11.0 Volts and the tablet's battery charge is above 30% before performing a software update to avoid update failure.
• During the update, do NOT leave the headlamp switch in auto mode, and turn OFF all other lamps and accessories.
• Do NOT disconnect any cables connected to the vehicle or scan tool during the update.
• Do NOT start the engine during the update.
• Do NOT turn OFF the ignition switch during the update.
• If the ECU update fails, remove the power connector from the in-cabin fuse box for at least 5 seconds, or disconnect the negative (-) 12V battery terminal then wait at least 5 seconds. Reassemble and retry the update.

Repair Procedure Summary

The repair involves updating the Data Communication Unit (DCU) software using specialized tools. The general steps are as follows:

1. Prepare for Update: Ensure the vehicle's battery and the diagnostic tablet are sufficiently charged. Turn off all unnecessary electrical components and ensure the ignition is in the ON position.
2. Connect Diagnostic Tools: Connect the Ethernet Communication Interface (ECI) DLC cable to the OBD connector, then connect the VCI DLC cable to the ECI, and finally connect the cable to the tablet PC. Refer to TSB 23-GI-006H for detailed Ethernet communication setup and TSB 25-GI-011H for the ECU Update Procedure for Tablet-Based GDS-Smart.
3. Perform ECU Update: Initiate the ECU update in Auto Mode using the GDS system. Technicians must verify the current ROM ID against the provided ROM ID Information table before proceeding.
4. Handle Update Failure (if any): If the update fails, follow specific instructions to reset the system (e.g., disconnecting battery power for at least 5 seconds) and retry the update. If Auto Mode continues to fail, the update can be performed in Manual Mode using a specific password (2419 for Event 1297, ECU Menu NX4 PE DCU 96510-N9140).
5. Post-Update Steps: After the ECU update reaches 100% completion, cycle the ignition OFF for 10-30 seconds to reset the control unit. Perform OTA (Over-the-Air) initialization, either automatically or manually via the S/W Management menu.
6. Final Checks: Take a screenshot of the update success screen for documentation. Perform an "All Systems Fault Code" search and erase any incidental DTC history that may have occurred during the update process. Start the engine to confirm proper operation.

Required Tools or Parts

Special Service Tools (SST) are required to perform this software update:

• VCI 3 (GOVHNNN06): Comes with the 19-Pin Cable (P/N G1XDDCA020).
• VCI 2 (G1XDDMN001): Requires the Ethernet Communication Interface (ECI) Kit (G0XDDMN052) to complete software updates.

The causal part for warranty claims is the ECU Part Number 96510-N9140.

ROM ID Information

To ensure the correct software version is applied, technicians must check the current ROM ID and update to the latest version. The ECU Part Number is 96510-N9140.

Model	Event	System	ECU Part Number	Current ROM ID	Latest ROM ID
Tucson (NX4)	1297	DCU	96510-N9140	120.NA.011509.011509, 120.NA.011606.011606, 120.NA.011646.011646, 120.NA.011951.011951	120.NA.012054.012054

Warranty Information

This service campaign is covered under warranty. Dealers should submit claims on the Claim Entry Screen as a “Campaign” type. The operation code for the DCU Software Update is 50D236R0, with an estimated operation time of 0.4 M/H. The causal part is 96510-N9140, with Nature Code W11 and Cause Code ZZ3.

If any other part requires replacement during this campaign and is under warranty, a separate claim should be submitted. For parts out of warranty, a Prior Approval request for goodwill consideration is required.

Owner Action

If you own a 2025 Hyundai Tucson (NX4), it is recommended to contact your authorized Hyundai dealer. They can check if your vehicle is affected by Service Campaign 25-01-059H and perform the necessary DCU software update to prevent the "DCU software error" and ensure your telematics services continue to function properly.

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Source: NHTSA ID: 11024805