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Service bulletin 21-01-048H

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 id10199097
Published by NHTSA2021-07-09
Manufacturer's number21-01-048H
Manufacturer's date2021-06-21
NHTSA componentENGINE AND ENGINE COOLING

NHTSA's summary

On certain 2021-2022 Elantra vehicles, a coolant leak at the Water Temperature Sensor (WTS) may be observed due to machining burrs at the mounting port of the cylinder head, resulting in improper coolant sealing.

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

Engine

Vehicles listed
HYUNDAI ELANTRA2021, 2022

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

Other bulletins for the same vehicles and component
26-EM-016H TSB2026-10-14. Service bulletin. Some vehicles equipped with internal combustion engines may exhibit higher-than-expected engine oil consumption. This bulletin outlines the combustion chamber cleaning procedure for vehicles diagnosed with this condition. All internal combustion engines consume some engine oil during normal operation, depending on driving conditions and mileage, and this procedure should only be performed when deemed necessary based on inspection and diagnosis of the vehicle as outlined in TSB 26-EM-015H, Engine Oil Consumption – Inspection & Repair Guidelines, or the latest revision.
26-EM-015H TSB2026-10-13. Service bulletin. Certain vehicles equipped with internal combustion engines may exhibit higher-than-expected engine oil consumption. This bulletin provides the inspection and repair procedures for vehicles exhibiting this condition. All internal combustion engines consume engine oil as part of normal engine operation. Oil consumption rates may vary based on mileage, operating conditions, driving habits, and maintenance history. Hyundai recommends following the prescribed maintenance schedule and periodically checking the engine oil level using the dipstick to maintain proper engine oil level.
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-EM-007H TSB2026-01-06. Service bulletin. Some Elantra (CN7, CN7A), Kona (OS, SX2), and Sonata Hybrid (DN8 HEV) vehicles equipped with 2.0L engines may illuminate a warning lamp for DTC P218100 (Cooling System Performance) related to the Integrated Thermal-Management Module (ITM). Follow the service procedure in this bulletin to install a spring onto the thermostat within the ITM, in order to prevent premature opening, and perform an ECU software update on affected vehicles.
24-FL-003H2024-04-02. Service bulletin. This bulletin contains the software update procedure for the Engine Control Unit (ECU) on certain 2021-2023MY Elantra (CN7) and 2022-2023MY Kona (OS) vehicles equipped with the 1.6 liter T-GDI Gamma 2 engine, that may exhibit a warning lamp with one or more of the DTCs listed below: • P250F - Engine Oil Level Too Low • P011B, P050C - Engine Coolant Temperature/intake Air Temperature Correlation • P00B7, P2B60 - Engine Coolant Flow Low/Performance
23-EM-005H2023-12-15. Service bulletin. This bulletin provides important checkpoint guidelines when performing engine oil and filter change services.
23-EE-010H2023-10-02. Service bulletin. This bulletin is issued to provide the extended battery diagnosis procedure using GDS-M. This battery diagnosis function displays the various battery-related faults such as: • Internal short circuit • Battery deterioration • Malfunction of electronic parts • Insufficient battery charge • Normal battery • Charging defect Battery diagnosis uses the battery sensor history saved for the last 30 days and ICU diagnostic communication to track battery state of charge (SOC) and current parasitic draw history.
22-EM-010H2022-08-05. Service bulletin. Follow the guidelines outlined in this bulletin to inspect and clean or replace certain components of the engine intake system accordingly during engine short block or sub-assembly replacement.
22-HC-001H2022-06-10. Service bulletin. If you are servicing an applicable model with Hybrid Drive Motor (Traction Motor) improper operation or any DTC listed in the related shop manual, Motor Control System, refer to the shop manual for diagnosis. If the diagnosis indicates a faulty hybrid drive motor, refer to the Service Procedure and replace the hybrid drive motor.
22-01-032H2022-04-08. Service bulletin. On certain 2021 Elantra and 2022 Kona vehicles equipped with 2.0L engine, a coolant leak at the Water Temperature Sensor (WTS) may be observed due to machining burrs at the mounting port of the cylinder head, resulting in improper coolant sealing.