P1A90 On Hyundai and Kia electric cars, a fault in the integrated charging control unit (ICCU), which supplies power to the 12-volt system

ICCU fault (Hyundai Ioniq 5, Kia EV6)

P1A90 in short

On Hyundai Ioniq 5 and Kia EV6, P1A90 goes with a failed integrated charging control unit (ICCU), which charges the 12-volt battery. Owners report a "stop vehicle" message, limited-speed turtle mode and a dead car. Treat it as do not drive, and have it towed to a dealer.

The ICCU on these electric cars charges the 12-volt battery from the high-voltage pack. When it fails, the 12-volt system can run down and the car limits speed or stops moving.

Owners of 2022 Ioniq 5 cars told NHTSA that the dealer found an ICCU fault and, in one case, a blown high-voltage fuse. Owners of 2022-2023 EV6 cars report P1A90 with a "stop vehicle and check power supply" message and a dealer-confirmed ICCU failure.

This page speaks only for Hyundai and Kia models in these owner reports. Other makes that use P1A90 may mean something different. High-voltage work is for trained technicians only.

Pick your make

P1A90 is a manufacturer-specific code: its meaning depends on who built the car.

Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.

Most likely causes

  1. Failed integrated charging control unit (ICCU)

    Supported by vehicle data
    Why it ranks here
    Dealers confirmed ICCU failure in complaints for a 2022 Ioniq 5 (ODI 11509852, 11702654) and a 2023 EV6 (ODI 11653352). These are owner complaints, not a bulletin.
    What would change this
    Rises if the 12-volt battery drains and the car shows a power-supply warning. Falls if a dealer finds a different fault.

  2. Blown high-voltage fuse that feeds the ICCU

    Possible — needs testing
    Why it ranks here
    One Ioniq 5 owner says the dealer found a blown high-voltage fuse and an ICCU fault after a pop sound from under the rear seat. One report is weak evidence.
    What would change this
    Rises if a pop is heard and the car loses drive power at once. Falls if the fuse tests good.

  3. A related high-voltage isolation fault

    Possible — needs testing
    Why it ranks here
    An EV6 readout stored P0AA6 (hybrid battery voltage system isolation fault) with P1A90, so a high-voltage fault may be present as well.
    What would change this
    Rises if P0AA6 is stored with P1A90. Falls if only P1A90 is stored.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. If the car shows a stop-vehicle or power-supply warning, stop in a safe place, turn the car off and call for a tow to a Hyundai or Kia dealer. Do not try to drive it or charge it.

    Best left to a shopTool: dealer scan tool

    Warning:High-voltage systems can cause serious injury or death. Only trained technicians should open or test them.

Symptoms

  • A "pull over", "stop vehicle" or "check electric vehicle system" message Gets more serious: stop and have it checked.
  • Speed limited to a low "turtle" mode Gets more serious: stop and have it checked.
  • 12-volt battery voltage drops and accessories stop Gets more serious: stop and have it checked.
  • A pop sound from under the rear seat before a warning

How to fix

We don't give DIY repair steps for a Stop code. Get the car inspected before you drive it; the tests above help you understand what a technician will check.

On your vehicle

Hyundai

  • 2022–2024 · Ioniq 5

    Supported by vehicle data

    Several 2022-2024 Ioniq 5 owners told NHTSA about P1A90 with an ICCU failure and a car that went into turtle mode or would not move; dealers confirmed ICCU failure. Complaints, not a bulletin.

Kia

  • 2022–2023 · EV6

    Supported by vehicle data

    Two EV6 owners told NHTSA about P1A90 with an ICCU failure after recall software updates; the dealer confirmed an ICCU failure. Complaints, not a bulletin.

  • P0AA6The hybrid computer has detected high voltage leaking to the vehicle body

    Shares causes Possible — needs testing

    An EV6 readout stored P0AA6 (high-voltage isolation fault) with P1A90; tell the dealer if both are stored.

All Hybrid and electric drive codes

P1A90 questions

Can I drive with P1A90?

No. Owners report the car going into a speed-limited mode or losing drive power. Stop safely and tow it to a Hyundai or Kia dealer.

Sources and review

  1. NHTSA complaint ODI 11509852 — NHTSA Office of Defects Investigation
  2. NHTSA complaint ODI 11653352 — NHTSA Office of Defects Investigation
  3. NHTSA complaint ODI 11702654 — NHTSA Office of Defects Investigation
  4. NHTSA complaint ODI 11697780 — NHTSA Office of Defects Investigation
Last reviewed
Written by
Saurabh K.
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