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Service bulletin 26-EM-009H TSB

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 id11030329
Published by NHTSA2026-03-30
Manufacturer's number26-EM-009H TSB
Manufacturer's date2026-03-24
NHTSA componentENGINE; ELECTRICAL SYSTEM

NHTSA's summary

Some Sonata (DN8) and Tucson (NX4/NX4A/NX4M) vehicles equipped with the 2.5L Theta III GDI engine may display a warning lamp and store Diagnostic Trouble Code (DTC) P2B59F0, which relates to the Integrated Thermal Management Module (ITM) circuit due to a logic error. This bulletin provides instructions to update the Engine Control Module (ECM) logic to correct this condition.

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, Engine

Trouble codes named

P2B59

Vehicles listed
HYUNDAI SONATA2024, 2025
HYUNDAI TUCSON2024, 2025

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

Recalls for the same vehicles and component
26V4000002026-06-23. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL
26V0470002026-01-26. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL
25V5490002025-08-25. ENGINE AND ENGINE COOLING:CRITICAL FASTENERS
24V8770002024-11-20. ELECTRICAL SYSTEM:WIRING

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
26-01-081H DCS2026-10-14. Service campaign. Certain Santa Fe Hybrid (TM HEV), Santa Fe Plug-in Hybrid (TM PHEV), Tucson Hybrid (NX4 HEV), andTucson Plug-in Hybrid (NX4 PHEV) vehicles may experience intake air line freezing and Exhaust GasRecirculation (EGR) valve corrosion due to excessive condensation accumulating within the EGR system.This condition can lead to drivability concerns related to the following DTCs: - P040400: (Exhaust Gas Recirculation Control Circuit Range) - P049D00: (EGR 'A' Control Position Exceeded Learning Limit) - P047100: (Exhaust Pressure Sensor 'A' Circuit Range/Performance) - P012800: Coolant Thermostat (Coolant Temperature below Thermostat Regulation Temperature) - P262B00: (Control Module Power Off Timer Performance) - P050C00: Cold Start Engine Coolant Temperature Performance - P1DFD00: (EVAP System Purge Pump Target Speed) - P2DFD00: (EVAP System Purge Pump Performance) - P112000: (Inlet Metering Valve – Malfunction) - P033500: (Crankshaft Position Sensor A)
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.
26-01-081H TSB2026-10-09. Service campaign. Certain Santa Fe Hybrid (TM HEV), Santa Fe Plug-in Hybrid (TM PHEV), Tucson Hybrid (NX4 HEV), and Tucson Plug-in Hybrid (NX4 PHEV) vehicles may experience intake air line freezing and Exhaust Gas Recirculation (EGR) valve corrosion due to excessive condensation accumulating within the EGR system. This condition can lead to drivability concerns related to the following DTCs: • P040400: (Exhaust Gas Recirculation Control Circuit Range) • P049D00: (EGR 'A' Control Position Exceeded Learning Limit) • P047100: (Exhaust Pressure Sensor 'A' Circuit Range/Performance) • P012800: Coolant Thermostat (Coolant Temperature below Thermostat Regulation Temperature) • P262B00: (Control Module Power Off Timer Performance) • P050C00: Cold Start Engine Coolant Temperature Performance • P1DFD00: (EVAP System Purge Pump Target Speed) • P2DFD00: (EVAP System Purge Pump Performance) • P112000: (Inlet Metering Valve – Malfunction) • P033500: (Crankshaft Position Sensor A) The bulletin below provides instructions to perform a software update for the Engine Control Module (ECM).
26-01-081H DN2026-10-09. Service campaign. Certain Santa Fe Hybrid (TM HEV), Santa Fe Plug-in Hybrid (TM PHEV), Tucson Hybrid (NX4 HEV), and Tucson Plug-in Hybrid (NX4 PHEV) vehicles may experience intake air line freezing and Exhaust Gas Recirculation (EGR) valve corrosion due to excessive condensation accumulating within the EGR system. This condition can lead to drivability concerns related to the following DTCs: • P040400: (Exhaust Gas Recirculation Control Circuit Range) • P049D00: (EGR 'A' Control Position Exceeded Learning Limit) • P047100: (Exhaust Pressure Sensor 'A' Circuit Range/Performance) • P012800: Coolant Thermostat (Coolant Temperature below Thermostat Regulation Temperature) • P262B00: (Control Module Power Off Timer Performance) • P050C00: Cold Start Engine Coolant Temperature Performance • P1DFD00: (EVAP System Purge Pump Target Speed) • P2DFD00: (EVAP System Purge Pump Performance) • P112000: (Inlet Metering Valve – Malfunction) • P033500: (Crankshaft Position Sensor A)
26-BE-025H TSB2026-09-09. Service bulletin. Some Tucson (NX4, NX4A, NX4M), Tucson Hybrid (NX4 HEV), and Tucson Plug-In Hybrid (NX4 PHEV) vehicles may exhibit a 12-volt battery drain due to the passive entry feature of the Digital Key 2 premium causing repeated wakeup of the vehicle. This bulletin provides instructions to perform software updates for the Ultra-Wide Band (UWB) and Body Domain Control (BDC) modules.
LA29-LA30 DCS2026-07-21. Warranty extension. Certain 2024-2026MY Sonata (DN8) and 2024-2026MY Sonata Hybrid (DN8 HEV) vehicles may exhibit intermittent battery discharge condition due to the air conditioning controller not fully powering down after the vehicle is turned off and parked. Technical Service Bulletins (TSB) 26-01-051H & 26-01-052H provide the procedure to update the ATCU (Air Temperature Control Unit) software; the revised logic improves controller shutdown to prevent battery drain and corrects a condition where the HVAC control display may appear blank when climate remote start is activated via Bluelink. Over-the-Air (OTA): This update can also be conducted via OTA. Customers can complete on their own if they have an active subscription to Hyundai Bluelink. A visit to the dealership is not required. Deployment of the OTA to Bluelink customers is planned to start the week of 07/13/26.
26-01-052H TSB2026-07-21. Warranty extension. Certain Sonata Hybrid (DN8 HEV) vehicles may exhibit intermittent battery discharge conditions due to the air conditioning controller not fully powering down after the vehicle is turned off and parked. This bulletin provides the procedure to update the Air Temperature Control Unit (ATCU) software; the revised logic improves controller shutdown to prevent battery drain and corrects a condition where the HVAC control display may appear blank when climate remote start is activated via Bluelink.
7/13/2026 TSB2026-07-21. Warranty extension. Certain Sonata (DN8) vehicles may exhibit intermittent battery discharge condition due to the air conditioning controller not fully powering down after the vehicle is turned off and parked. This bulletin provides the procedure to update the ATCU (Air Temperature Control Unit) software; the revised logic improves controller shutdown to prevent battery drain and corrects a condition where the HVAC control display may appear blank when climate remote start is activated via Bluelink.
26-EE-007H TSB2026-06-23. Service bulletin. Some Palisade (LX2), Tucson (NX4), and Tucson Hybrid (NX4 HEV) vehicles may experience battery drain due to continuous operation of the cooling fan after vehicle ignition has been turned off, potentially resulting in a no-start condition. The continuous cooling fan operation is caused by a stuck relay in the engine room PCB block. This bulletin provides instructions to replace the engine room PCB block to ensure the proper operation of the cooling fan.