ICCU Fault in Hyundai IONIQ 5, IONIQ 6 and Kia EV6: Symptoms, Recall and Part Identification

In the Hyundai IONIQ 5 and IONIQ 6 and Kia EV6 owner groups, cases involving a dead 12-volt system, charging problem or loss of power while driving are often referred to simply as "ICCU errors". However, the symptom itself is not a diagnosis: a weak 12-volt battery, a wiring error, or a fault in another control unit can also cause a similar phenomenon. For an accurate determination, vehicle-specific manufacturer-level diagnostics and campaign data corresponding to the VIN are required.

What is an ICCU and what happens when it fails?

ICCU stands for Integrated Charging Control Unit. According to Hyundai's US recall notice, the unit supports, among other things, the charging of the 12-volt auxiliary battery and the power supply of low-voltage consumers. The high-voltage drive battery and the 12-volt system are therefore two separate systems, but they work closely together through the ICCU.

Hyundai and Kia documents describe electrical and thermal load conditions that can damage the ICCU. If the charging of the 12-volt battery is interrupted because of this, its energy level may gradually decrease while driving. The vehicle will first warn and then limit performance in protection mode. Ignoring the signs can eventually lead to loss of drive.

Which models were affected by the documented campaigns?

In the United States, Hyundai campaign number 24V-868 covered certain 2022-2024 IONIQ 5, 2023-2025 IONIQ 6, Genesis GV60, Electrified GV70, and Electrified G80 vehicles. The campaign expanded and replaced the previous 24V-204 recall; the new measure may also have become necessary for previously repaired cars. Kia's 24V-867 and SC327 campaigns respectively covered certain 2022-2024 EV6 and EV6 GT vehicles and replaced the previous SC302 campaign.

These are American campaign identifiers and model year ranges, so they do not automatically prove the involvement of a Hungarian or other European car. Even within the same model year, the date of manufacture, the market, the drive version and the built-in hardware version may matter. In all cases, the decisive verification key is the full 17-character VIN.

What symptoms should you pay attention to?

Kia's owner's bulletin lists several possible indications: beep, "Check electric vehicle system," charging system or main warning, "Stop vehicle and check power supply" message, turtle icon, and reduced drive power. The display text may differ depending on the model and language setting. A repeatedly discharged 12-volt battery can also be a practical warning sign, but this alone does not prove that the ICCU is faulty.

• A red or yellow warning will appear indicating an electrical system or charging system.
• The vehicle's performance is reduced or the restricted mode indicated by the turtle icon is activated.
• The 12-volt battery will die again in a short time, even though it has been checked or replaced.
• manufacturer-level diagnostics will find an active or historical P1A9096 DTC in the ICCU system.
• The dealership indicates an open ICCU campaign for the vehicle's VIN.

If a power drop or a stop message is displayed while driving, do not try to "walk away" from the remaining 12 volt energy. Pull over to a safe place, stop the vehicle according to the owner's manual and ask for professional help or transportation. Clearing the warning, temporarily feeding or replacing the 12 volt battery does not make the ICCU proven fault-free.

What does recall repair do?

The common logic of the public Hyundai and Kia procedures is that the service center first checks the campaign coverage and the diagnostic error code. If P1A9096 is not stored, updating the prescribed ICCU software may be the necessary action. If the error code is present, the docs describe replacing the ICCU and high voltage fuse, then checking or updating the appropriate software version. The specific European procedure is always determined by the current manufacturer campaign for the given VIN.

Updating the navigation or infotainment system at home is not the same as updating the ICCU control software with a factory diagnostic tool. It is worth confirming the end of the campaign with a worksheet or the status recorded in the manufacturer's system.

ICCU part number and compatibility: why is the label not enough?

Hyundai US service bulletin 24-01-086H-1 lists campaign part number 36400-1XAA0QQH for 2022-2024 IONIQ 5, 36400-1XEA0QQH ICCU for 2023-2025 IONIQ 6, and fuse number 375F2-GI040QQH. These are service numbers for a specific market and recall procedure: they cannot be considered as an order or replacement guarantee valid for all European cars.

Kia bulletin SC327 specifically states that the ECU part number for a given vehicle should be found in the electronic parts catalog and not solely based on the label affixed to the unit. This is because the hardware, ROM and software versions, as well as the changes introduced during the campaign, together determine compliance.

• To search for parts, enter the complete VIN, model code, production date and drive version.
• Request the original and the so-called supersession part number that caused it from the current OEM electronic parts catalogue.
• Check whether the hardware and software status of the used component corresponds to the current campaign specification of the vehicle receiving the part.
• For used units, ask for a legible photo of the label, donor VIN, inspection report and warranty conditions.
• Do not treat the ICCU fuse as a separate fuse that can be replaced by a layman: the manufacturer procedure ties it to sequence and high-voltage work.

Before buying a used IONIQ 5, IONIQ 6 or EV6

The test round alone is not enough. Ask for the 17-character VIN before viewing, and have it checked in the Hungarian brand network to see if there is an open recall or service campaign. Ask for proof of a previous ICCU upgrade or replacement, especially if the seller just says "there was a recall". The completion of the previous campaign did not always mean the automatic closure of the later, expanded campaign.

During an independent, EV-specialized condition assessment, it is worth reading the active and historical error codes, having the 12-volt battery checked, and testing AC and — with the right infrastructure — DC charging. A health check is not a substitute for a manufacturer's campaign check, but it does help isolate a recurring 12 volt problem, charging failure, and other electrical abnormalities.

In short: without a VIN, there is no definite answer

ICCU failure is a real and documented safety risk, but not all IONIQ 5, IONIQ 6, or EV6 are defective, and not all 12 volt discharges are of ICCU origin. The correct sequence: VIN-based campaign control, manufacturer-level diagnostics, following the current repair regulations, and only then purchasing parts. This simultaneously reduces the risk of misdiagnosis, incompatible unit and dangerous high voltage intervention.