2022-2024 Hyundai Ioniq ICCU Charging Fault TSB 24-EV-004H

Hyundai has issued Technical Service Bulletin (TSB) 24-EV-004H, superseding previous bulletin 23-EV-004H, to address specific repair procedures for the Integrated Charge Control Unit (ICCU) in certain 2022-2024 Hyundai Ioniq 5 and Ioniq 6 models. This bulletin is crucial for resolving issues related to the Hyundai Ioniq ICCU charging system, including concerns with DC to DC charging and inoperative AC charging.

The TSB outlines the correct method for replacing the ICCU and its associated fuse to ensure proper vehicle function and prevent potential damage to other components, such as the Power Relay Assy (PRA). Owners experiencing charging problems with their Ioniq vehicles should be aware of these specialized repair instructions.

Symptoms of an ICCU Charging Fault

Owners of affected Hyundai Ioniq vehicles may notice issues with their vehicle's charging capabilities. These can include a "DC to DC related charging concern" or experiencing "inoperative AC charging," where the vehicle fails to charge using an AC power source. These symptoms indicate a potential problem with the Integrated Charge Control Unit.

Fault Codes / DTCs

Diagnostic Trouble Codes (DTCs) can help identify an ICCU-related charging problem. The TSB specifically mentions:

• P1A9096: This DTC is associated with DC to DC related charging concerns, indicating a fault within the ICCU's DC-to-DC converter function.
• P1B77: This code points to potential damage to the Power Relay Assy (PRA) in the EV Battery. This damage can occur if the ICCU fuse is replaced without simultaneously replacing the ICCU itself.

Important Warnings for Owners

Hyundai's TSB 24-EV-004H includes several critical warnings to ensure proper repair and prevent further vehicle damage or delays:

• "The ICCU fuse accessible from a rear side panel of the EV Battery, should NEVER be replaced by itself prior to receiving an ICCU replacement part."
• "The ICCU fuse should be replaced at the same time as replacing the ICCU part."
• "DTC P1B77 Power Relay Assy (PRA) damage in the EV Battery can occur when an ICCU fuse is first replaced without also replacing the ICCU together."
• "Vehicles with P1B77 require Techline approval for field staff involved EV Battery repair and can result in significant additional delay for customers."
• "Wait to receive ICCU replacement part first before also replacing the ICCU fuse on the rear side of the EV battery."
• "To avoid any potential damage to IONIQ vehicles, IONIQ repairs can only be performed at IONIQ certified dealers."

These warnings highlight the importance of a complete and synchronized replacement procedure for both the ICCU and its fuse, and the necessity of specialized dealer intervention.

Repair Procedure Summary

The repair procedure outlined in TSB 24-EV-004H involves several steps to address the Hyundai Ioniq ICCU charging issue. Technicians will first shut off the high-voltage circuit by pulling out the service interlock connector and allowing capacitors to discharge. This is a critical safety step.

Next, the Integrated Charge Control Unit (ICCU) assembly, located under the rear seat, is removed and replaced. Following this, the rear under cover is removed to access the ICCU high-voltage connector and its cover, which are then disconnected and removed. The ICCU fuse cover is also removed.

The ICCU fuse itself is carefully removed. Technicians are advised to be cautious during this step, as the nuts holding the fuse in place have been known to fall into the battery. The fuse is inspected for an open circuit using an ohmmeter, and if confirmed faulty, it is replaced with a new, supplied ICCU fuse. All components are then reinstalled in the reverse order of removal, with specific tightening torques applied to bolts and nuts.

Special instructions are provided for situations where a nut falls back into the battery during fuse removal, detailing a specific procedure to retrieve it. If this procedure does not resolve a dropped nut problem, technicians are instructed to contact Techline.

Owner Action

If you own a 2022-2024 Hyundai Ioniq 5 (NE1, NER) or Ioniq 6 (CE1) and are experiencing issues such as "inoperative AC charging," "DC to DC related charging concern," or if your vehicle has diagnostic trouble codes P1A9096 or P1B77, it is important to contact an IONIQ certified Hyundai dealer. Do not attempt to replace the ICCU fuse yourself, as this can lead to further damage. The repairs described in TSB 24-EV-004H are covered under normal warranty. Your dealer will follow the specific instructions in TSB 24-EV-004H to properly diagnose and repair the Hyundai Ioniq ICCU charging system.

Source: NHTSA TSB ID: 11006095