2022-2025 Hyundai Ioniq 5 / Ioniq 6 VCU Limp Home Enhancement

Hyundai has released Service Campaign 24-01-088H to update the Vehicle Control Unit (VCU) software in certain 2022-2025 IONIQ 5 and IONIQ 6 electric vehicles. This update aims to enhance the vehicle's "limp home" functionality, specifically when the 12V battery voltage drops below operational levels, causing the VCU to activate a "fail-safe" mode. The software modification adjusts the maximum vehicle speeds allowed during this "fail-safe" condition, helping to prevent potential damage and ensure safer operation.

Important Warnings and Notices

Owners and dealers should be aware of the following critical information regarding this service campaign:

• Dealers must perform this service campaign on all affected vehicles prior to customer retail delivery. It must also be performed whenever an affected vehicle is in the shop for any maintenance or repair.
• To avoid any potential damage to IONIQ vehicles, this service campaign can only be performed at IONIQ certified dealers.
• 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.
• If the GDS system displays a "Warning! lower Battery Voltage. BATTERY VOLTAGE: 11.7" or similar message indicating the voltage is below 12 Volts, you must attach a battery charger to ensure an adequate battery charge before attempting the update. Turn the ignition back ON and retry the ECU update.
• If the update fails, remove the power connector or the battery (–) connector from the indoor fuse box for at least 5 seconds and reassemble it to retry the update.

Symptoms

Owners of affected 2022-2025 Hyundai Ioniq 5 and Ioniq 6 vehicles may experience a condition while driving where the 12V battery voltage drops. This voltage drop can cause the Vehicle Control Unit (VCU) to place the vehicle into a "fail-safe" mode. While in this mode, the vehicle's performance will be limited to protect its systems. Technicians performing the update might encounter a warning message on the GDS system stating, "Warning! lower Battery Voltage. BATTERY VOLTERY: 11.7". This indicates the need for a battery charge before proceeding with the software update.

Repair Procedure Summary

The repair involves updating the Vehicle Control Unit (VCU) software using the Global Diagnostic System (GDS). The process, identified by operation code 40D229R0, typically takes 0.7 hours to complete. The update procedure is as follows:

1. Initial Update in Auto Mode: The GDS ECU update must first be attempted in Auto Mode. If this fails, the update should be performed in Manual Mode.
2. ROM ID Verification: Technicians must use the ID Check function to verify the current ROM ID version and compare it against the ROM ID information table provided in the bulletin before proceeding with the software update.
3. Ignition Cycle: After the ECU update process shows 100% completion, the ignition must be cycled OFF for at least 10 seconds (up to 30 seconds for some models) to reset the control unit.
4. Screenshot Documentation: A screenshot of the ECU update complete screen must be taken and uploaded to STUI for repair validation.
5. DTC Clearance: An "All Systems Fault Code" search must be performed, and any incidentally stored Diagnostic Trouble Code (DTC) history from the ECU update must be erased.
6. Operation Confirmation: The vehicle should then be started in "Ready" mode to confirm proper operation.

For specific details on the ECU update procedure using the Tablet-Based GDS-Smart, technicians are advised to refer to TSB # 24-GI-012H.

Required Tools or Parts

To perform this VCU software update, a Global Diagnostic System (GDS) is required. Additionally, a battery charger may be necessary if the vehicle's 12V battery voltage is low. The VCU part numbers associated with this update are 39751-1XNN1 for the IONIQ 5 and 39751-1XEN1 for the IONIQ 6. The new ROM IDs after the update will be NE1A-N0-SB9-V400 or NE1A-N0-KB9-V200 for IONIQ 5, and 397511XEN1_NS02 or 397511XEN2_NK02 for IONIQ 6.

In cases where the update fails in Auto Mode and Manual Mode is required, specific passwords are provided:

• Event #1165 (IONIQ 5):
  • NE EV VCU 39751-1XNN1: 1579
  • NE EV VCU 39751-1XNN4: 4115
• Event #1194 (IONIQ 6):
  • CE EV VCU 39751-1XEN1: 5121
  • CE EV VCU 39751-1XEN2: 5122

Owner Action

If you own a 2022-2025 Hyundai Ioniq 5 or Ioniq 6, it is recommended to contact your local Hyundai IONIQ certified dealer to schedule this VCU software update. This service campaign, identified as 24-01-088H, is a software update and will be performed free of charge. The update is crucial for ensuring the proper functionality of the Hyundai Ioniq 5 VCU limp home system, especially under conditions of low 12V battery voltage.