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Service bulletin 21-01-056H

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10200074
Published by NHTSA2021-08-07
Manufacturer's number21-01-056H
Manufacturer's date2021-07-30
NHTSA componentELECTRICAL SYSTEM

NHTSA's summary

Some 2021 Elantra (CN7) vehicles may exhibit a condition with multiple warning lights displayed on the instrument cluster and various symptoms; multiple DTCs (Diagnostic Trouble Code), reduction in power steering assist, and not able to shift out of Park. Possible DTCs set are: • C181287 – CAN Time-out Gateway • C181208 – CAN Time-out Gateway • C180581 – LKAS CAN Signal Error • C181887 – CAN Time-out BCA • B109052 – TCU Missing Error

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Electrical system

Trouble codes named

B1090, C1805, C1812, C1818

Vehicles listed
HYUNDAI ELANTRA2021

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
23V5890002023-08-18. ELECTRICAL SYSTEM; VEHICLE SPEED CONTROL

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
26-EE-003H TSB2026-04-21. Service bulletin. Some vehicles may exhibit difficulty starting in cold weather. This bulletin provides the procedure to perform an inspection on the starter magnetic switch for potential freezing and, if necessary, replace the starter magnetic switch (solenoid) assembly.
25-01-089H DCS2026-01-06. Other. Upon customer's request ONLY, the Technical Service Bulletin (TSB) 25-01-089H provides the service procedure for installation of a key cylinder reinforcement protector assembly and two anti-theft decals on the front windows. This repair procedure is being provided in addition to the previous Anti-Theft software provided under Service Campaign 993 (TSB 24-01-009H-1).
25-01-089H DN2026-01-06. Other. In addition to the Anti-Theft software provided under Service Campaign 993 (TSB 24-01-009H-1), a zinc reinforced ignition cylinder protector hardware upgrade is being made available to customers upon request. This supplemental security measure is to be installed at the ignition switch location and provides additional protection against the social media theft method. Vehicles not equipped with an immobilizer during production at the factory are eligible. The repair procedure shall be performed and claimed upon customer request only. Any future repairs to these vehicles in which an installed ignition cylinder protector impacts required parts and/or labor, shall be covered by HMA. Please see TSB 25-01-089H for details.
25-01-089H TSB2026-01-06. Other. This bulletin provides the service procedure for installation of a key cylinder reinforcement protector assembly and two anti-theft decals on the front windows.
P33 OL2025-12-19. Other. In response to this trend, we engineered a software upgrade that addresses the social media theft method and made it available to owners of eligible models free of charge at authorized Hyundai dealers since early 2023. In addition to the anti-theft software, we’ve developed a new zinc-reinforced ignition cylinder protector hardware upgrade that can be installed at the ignition cylinder location to provide additional protection against the social media theft method. Because your Hyundai vehicle with the VIN listed above (“Subject Vehicle”) was not factory-equipped with an engine immobilizer and was previously eligible for the software upgrade, you are now eligible until March 31, 2027 to have the ignition cylinder protector installed — if you request it — at no cost to you through an authorized Hyundai dealership.
25-BE-020H TSB2025-10-03. Service bulletin. This bulletin provides information related to the changes introduced in the 2025 1st Navigation Map and Software Update. The changes may vary depending on vehicle type, model, and navigation system as described in this TSB.
25-01-010H-1 9B4 OL2025-08-22. Service campaign. Certain Hyundai vehicles may exhibit a warning light with Diagnostic Trouble Code (“DTC”) P1BB20 due to a battery over voltage condition.
25-01-010H-1 DN2025-07-22. Service campaign. Certain Elantra Hybrid (CN7 HEV), Sonata Hybrid (DN8 HEV), and Tucson Hybrid (NX4 HEV) vehicles may exhibit a warning light due to DTC Code P1BB20 (12V Lithium Battery Cell Voltage High). The California Air Resources Board has determined that these vehicles may be releasing air pollutants which exceed Federal and California standards.
25-01-010H-1 TSB2025-07-22. Service campaign. This bulletin provides the procedure to update the software for the Battery Management System (BMS) on certain Elantra Hybrid (CN7 HEV), Sonata Hybrid (DN8 HEV), and Tucson Hybrid (NX4 HEV) vehicles that may exhibit a warning light with DTC P1BB200 and enter Limp Mode.
25-BE-002H TSB2025-06-03. Service bulletin. This bulletin provides information related to the changes introduced in the 2024 2nd Navigation Map and Software Update. The changes may vary depending on vehicle type, model, and navigation system. Refer to the 2024 2nd Navigation Map and Software Update Improvements section in this TSB for a list of specific changes. The software can be downloaded via Navigation Updater (NAU) and updated by USB. The NAU website is https://update.hyundai.com/US/EN/navigationUpdate. For certain models equipped with a relevant Bluelink package, the software may be downloaded and applied via OTA update.