P1A90: DC/DC Converter Input Voltage Sensor Fault (ICCU)
2 vehicles · 2 makes
Most Reported On
P1A90 is an OBD-II diagnostic trouble code meaning “DC/DC Converter Input Voltage Sensor Fault (ICCU).” Stored by the Integrated Charging Control Unit, which bundles the on-board charger, DC-DC converter, and vehicle-to-load export hardware into one box. The module reports an implausible or out-of-range input-voltage sensor reading on the DC-DC converter stage, meaning the ICCU can no longer reliably step the high-voltage pack down to charge the 12-volt battery. Hyundai/Kia/Genesis service documentation carries it as the sub-coded fault P1A9096 in the ICCU inspection, fuse-replacement, and software-update campaign. Once the ICCU stops feeding 12 volts, the 12V battery drains and the vehicle progressively loses accessories, then drive power. This code is most commonly reported on 2023-2025 Genesis GV70 (Electrified GV70, Electrified GV70 Advanced, Electrified GV70 Prestige), and 2022-2024 Hyundai Ioniq 5.
Common Causes
Diagnostic Tools
P1A90 does not use the standard P/B/C/U prefix. It may be a manufacturer-specific code, so verify that a scanner supports your exact year, model and module before buying.
FAQ
What does P1A90 mean?
P1A90 stands for "DC/DC Converter Input Voltage Sensor Fault (ICCU)." Stored by the Integrated Charging Control Unit, which bundles the on-board charger, DC-DC converter, and vehicle-to-load export hardware into one box. The module reports an implausible or out-of-range input-voltage sensor reading on the DC-DC converter stage, meaning the ICCU can no longer reliably step the high-voltage pack down to charge the 12-volt battery. Hyundai/Kia/Genesis service documentation carries it as the sub-coded fault P1A9096 in the ICCU inspection, fuse-replacement, and software-update campaign. Once the ICCU stops feeding 12 volts, the 12V battery drains and the vehicle progressively loses accessories, then drive power.
What are the most common causes of P1A90?
The most common causes of P1A90 are: ICCU internal failure (DC-DC converter stage) on E-GMP platform vehicles, Blown ICCU input fuse following an ICCU fault event, Outdated ICCU control software (addressed by manufacturer software update), 12-volt battery repeatedly deep-discharged by a failing ICCU. The specific cause varies by vehicle.
How much does it cost to fix P1A90?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P1A90?
Au7o has documented P1A90 across 2 vehicle models from 2 manufacturers: Genesis, Hyundai.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.