P1A90 fault code: what it means

P1A90: ICCU (charging unit / DC-DC converter) fault on Ioniq 5 and Ioniq 6. 12V battery stops charging; power fades in fail-safe mode and can be lost. Recall 24V868.

Engine and gearbox (powertrain) · Safety risk

Usual causes, most likely first

failed ICCU (internal MOSFET fails and blows the ICCU fuse)
blown ICCU fuse
ICCU software not updated (recall 24V868)
flat or damaged 12V battery

P1A90 by make

Hyundai

ICCU (charging unit / DC-DC converter) fault on Ioniq 5 and Ioniq 6. 12V battery stops charging; power fades in fail-safe mode and can be lost. Recall 24V868.

Usual causes: failed ICCU (internal MOSFET fails and blows the ICCU fuse); blown ICCU fuse; ICCU software not updated (recall 24V868); flat or damaged 12V battery

Kia

ICCU (charging unit / DC-DC converter) fault on EV6 and other E-GMP EVs. 12V battery stops charging and the car can lose drive power.

Usual causes: failed ICCU (internal transistor blows the 12V feed fuse); blown ICCU fuse; ICCU software not updated (recall); flat or damaged 12V battery

What the repair usually costs

Hybrid 12 V auxiliary battery (Aqua / Prius C / Axio, S34B20R)NZ$330–NZ$510 · A$310–A$500
Hybrid 12 V auxiliary battery (Prius 30 / Prius alpha / CT200h, S46B24R AGM)NZ$390–NZ$690 · A$360–A$590
Hybrid 12 V auxiliary battery (Camry / RAV4 / C-HR / Lexus, S55D23R or LN1-LN2 AGM)NZ$420–NZ$770 · A$390–A$730
EV 12 V battery replace (Nissan Leaf / e-NV200, lead-acid)NZ$200–NZ$340 · A$210–A$380

Not sure what P1A90 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.