2022-2023 Hyundai Tucson Check Engine Light DTC P218100

Owners of certain 2022-2023 Hyundai Tucson vehicles may encounter an illuminated Check Engine Light accompanied by specific diagnostic trouble codes (DTCs) related to the cooling system. Hyundai Technical Service Bulletin (TSB) 26-EM-004H addresses this concern, providing a comprehensive solution for the affected vehicles.

This TSB outlines the necessary steps to resolve issues indicated by DTC P218100, P2181F0, and P2181F1, which point to a "Cooling System Performance" problem within the vehicle's Electronic Control Unit (ECU). The repair involves replacing the Integrated Thermal Management (ITM) module and performing critical software updates for both the Engine Control Module (ECM) and, if applicable, the Transmission Control Module (TCM).

Symptoms and Warning Lights

Owners of affected 2022-2023 Hyundai Tucson models will primarily notice the illumination of the Check Engine warning lamp on their dashboard. This warning indicates that the vehicle's Electronic Control Unit (ECU) has detected a fault within the cooling system, specifically related to its performance.

Diagnosing the Issue: Fault Codes

The primary indicators for this issue are specific diagnostic trouble codes (DTCs) stored in the vehicle's ECU. Technicians will use a diagnostic scan tool to confirm the presence of these codes.

Code	Description	Module
P218100	Cooling System Performance	ECU
P2181F0	Cooling System Performance	ECU
P2181F1	Cooling System Performance	ECU

This TSB, 26-EM-004H, explicitly states that it ONLY applies if these specific DTCs (P218100, P2181F0, and/or P2181F1) are detected during the diagnostic process. If these codes are not present, the TSB's repair procedures are not applicable, and further diagnosis for other issues should be pursued.

Important Warnings and Owner Advisories

Hyundai has issued several critical warnings and advisories within TSB 26-EM-004H that owners and technicians should be aware of:

• Repair Justification: "This field action requires justification in the form of a customer concern, and a confirmed case for the related symptom outlined in the TSB, prior to any repair work. If justification requirements are not met, any submitted claims are subject to debit."
• Antifreeze Usage: "Do NOT use 100% full strength antifreeze. Prepare coolant mixed with distilled/filtered water to refill the cooling system (35-50% antifreeze, diluted with distilled/filtered water)."
• ITM Replacement Timing: "For proper engine operation, ITM replacement MUST be completed before the ECU update."
• Software Update Precautions: During software updates, technicians are advised to ensure the vehicle's battery charge is above 11.0 Volts and the diagnostic tablet's battery charge is above 30%. They must also "Turn OFF all lamps (do NOT leave head lamp switch in auto mode) and all accessories."
• Update Interruption: "Do NOT disconnect any cables connected to the vehicle or scan tool during the update." and "Do NOT start the engine during the update." Also, "Do NOT turn OFF the ignition switch during the update."
• Radiator Cap Safety: "Do NOT remove the radiator cap when the engine is hot. Serious scalding could occur by hot fluid under high pressure escaping from the radiator."
• Coolant Filling Procedure: "Failure to follow the ITM bleeding procedure under S/W Management in GDS may result in air pockets and overheating of the engine."

The Repair: Integrated Thermal Management Module and Software Updates

The resolution for the Hyundai Tucson DTC P218100 issue involves a multi-step process. First, the Integrated Thermal Management (ITM) module is replaced. Following this, software updates are performed on the Engine Control Module (ECM) and, if applicable, the Transmission Control Module (TCM). The process concludes with a specific coolant filling procedure to ensure proper system operation.

Required Parts and Tools

To perform the repair outlined in TSB 26-EM-004H, specific parts and tools are required:

• Control Assy – Coolant Temperature: Part Number 25600-2S650QQH (Quantity: 1)
• O-Ring: Part Number 25462-2S000 (Quantity: 1)
• Pink Antifreeze/Coolant: Part Number 00232-19098 (Quantity: 2 gallons)

Special Service Tools (SST) for software updates include VCI 3 (GOVHNNN06) and VCI 2 (G1XDDMN001). Note that VCI 2 is no longer available for order but can still be used for updates.

Detailed Repair Procedure Summary

1. DTC Check: A technician will use the GDS (Global Diagnostic System) to scan for DTCs P218100, P2181F0, and/or P2181F1. If these codes are not present, the TSB does not apply.
2. ITM Replacement: The Integrated Thermal Management (ITM) module is replaced. This involves following the detailed repair procedures found in the shop manual under "Engine Mechanical System > Cooling System > Integrated Thermal Management Module (ITM) > Repair procedures." All removed parts are then reinstalled in reverse order.
3. ECM Software Update: The Engine Control Module (ECM) software is updated using Event #1281. This update must be performed in Manual Mode. Technicians refer to TSB 25-GI-011H for specific instructions on using the tablet-based GDS-Smart system. The current ROM ID is verified, and if the update fails, the power connector from the in-cabin fuse box is removed for at least 5 seconds before retrying. After a successful update, the ignition is cycled OFF for 10-30 seconds, and a screenshot of the "Success" screen is taken for documentation.
4. TCU Software Update (if applicable): For vehicles equipped with ISG (Idle Stop & Go) and a 2.5L GDI engine, the Transmission Control Module (TCM) software is updated. This applies to 2022MY vehicles with VINs starting with "KMH" (Event #1032) or "5NM" (Event #1034). The update is performed in Auto Mode, and the current ROM ID is verified. If the TCU update fails, the power connector from the in-cabin fuse box or the negative 12V battery terminal is disconnected for at least 5 seconds before retrying.
5. ITM Coolant Filling Mode: After the hardware replacement and software updates, the Integrated Thermal Module Coolant Filling Mode is performed using the GDS. This procedure, detailed in the shop manual under "Engine Mechanical System > Cooling System > Coolant > Repair procedures," assists in refilling the coolant and bleeding the system. The vehicle is then started to confirm normal operation.
6. DTC History Erase: Finally, an All Systems Fault Code search is performed, and any incidentally occurring DTC history from the ECU update is erased.

Warranty Information

This repair falls under an 8-year / 80,000-mile Emissions Warranty. Claims for this service must be submitted as a "Campaign" type. Prior to any repair, technicians must verify that the affected parts are within the emissions warranty coverage based on mileage and warranty start date. If parts are out of warranty, dealers may submit a Prior Authorization (PA) Request for goodwill consideration on a case-by-case basis. The TSB also notes that repair justification, including automatically uploaded DTCs via GDS e-Report and required photos of the ECU Update "Success" screen, is necessary for claim submission. Incident parts may be subject to callback, and claims may be debited if parts are not returned.

Next Steps for Owners

If your 2022-2023 Hyundai Tucson is exhibiting a Check Engine Light and you suspect a "Cooling System Performance" issue, especially if you have previously had it diagnosed with DTC P218100, P2181F0, or P2181F1, you should contact your authorized Hyundai dealership. Inform them about the symptoms and reference TSB 26-EM-004H. The dealership will perform the necessary diagnostic checks and, if applicable, carry out the ITM replacement and software updates under warranty.

Source: NHTSA ID 11028667