Hyundai bulletin 23-01-072H
What it saysThis bulletin provides the procedure to update the Hybrid Control Unit (HCU) / Low DC/DC Converter (LDC) software logic to eliminate internal P-DTCs (that are not viewable) in certain 2019-2021MY IONIQ Hybrid (AE HEV)… NHTSA’s full summary ↓
Hyundai filed this with NHTSA as a service bulletin dated Sep 7, 2023, received Oct 2, 2023, about the power train. It names 3 model years (2019–2021). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationWhat it applies to, as the document itself states it — the build window in the manufacturer’s own words, read by machine from the PDF NHTSA serves. The build date is on the certification label in the driver’s door jamb; the dealer settles a borderline vehicle by its VIN.
This bulletin provides the procedure to update the Hybrid Control Unit (HCU) / Low DC/DC Converter (LDC) software logic to eliminate internal P-DTCs (that are not viewable) in certain 2019-2021MY IONIQ Hybrid (AE HEV) and 2021MY IONIQ Plug-in Hybrid (AE PHEV) vehicles.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 23-01-072H | Service bulletin | Sep 7, 2023 | 10243318 | PDF, 1,059 KB |
What the document itself lists
The manufacturer titles it “HCULDC SOFTWARE UPDATE FOR P-DTC”.
Parts the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| 36600-2B133 | — | — | |
| 36600-2B180 | — | — | |
| 36600-2B181 | — | — | |
| 36600-2B580 | — | — | |
| 36600-2B183 | — | — | |
| 36600-2B582 | — | — | |
| 36600-2B186 | — | — |
Read by machine from the document NHTSA serves (11 pages), read Sep 30, 2026. A part number is shown only where it matches Hyundai’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote. Listings and prices on eBay Motors are the seller’s.
Affiliate disclosure: some links on this page are affiliate links. If you request a quote or buy through them we may earn a commission at no extra cost to you. Nothing on this page changes because of it.
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Doing the repair yourself, or pricing it before the shop does? Search the part by fitment on eBay Motors — the listing and the price are the seller’s.
Find the software for the 2021 Ioniq →Affiliate disclosure: some links on this page are affiliate links. If you request a quote or buy through them we may earn a commission at no extra cost to you. Nothing on this page changes because of it.
Model years it names
Source: as the manufacturer filed themA vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 3 model years this bulletin names have filed 84 complaints with NHTSA since 2015. 39 of them name Electrical System, Power Train — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
VEHICLE SAFETY HAZARD: ACTIVE HIGH-VOLTAGE ISOLATION FAULT (DTC P0AA6) WITH DECEPTIVE DEALER/MANUFACTURER BYPASS & CONCEALMENT. On April 15, 2026, the dealer scanned my 2021 Ioniq EV and uncovered DTC P0AA6 (Hybrid/EV Battery Voltage System Isolation Fault), which denotes a catastrophic high-voltage leak into the chassis.
2021 Hyundai Ioniq · Electrical System · filed with NHTSA Jul 16, 2026 · ODI 11750854
When the engine is turned off, and the car is not in park, it rolls. When the engine is turned off the car should automatically switch to P to prevent it from rolling. Our car was left in R with the engine off. And instead of switching to P automatically, it just rolled away and hit the neighbors garage
2020 Hyundai Ioniq · Power Train · filed with NHTSA Jan 8, 2026 · ODI 11709810
Component that failed: The charging inlet locking actuator (Hyundai: "charging connector lock/unlock actuator") on my 2019 Hyundai IONIQ Plug-In Hybrid. It locks the connector to the inlet. The failed actuator is STILL INSTALLED and available for inspection at a dealership.
2019 Hyundai Ioniq · Electrical System · filed with NHTSA Oct 20, 2026 · ODI 11772541
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Hyundai, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Hyundai 23-01-072H a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the 23-01-072H repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way. Every Hyundai warranty extension on file lists the ones Hyundai has filed.
Which vehicles does 23-01-072H cover?
The manufacturer filed it against 3 model years: 2021 Hyundai Ioniq, 2020 Hyundai Ioniq, 2019 Hyundai Ioniq. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone. The document itself sets the build window: built 4 Dec 2018 – 8 Dec 2018; built 28 Sep 2020 – 5 Feb 2021; built 4 Dec 2020 – 5 Feb 2021 — the build date is on the certification label in the driver’s door jamb.