# Service bulletin TSB\_ENG258

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.

- Type: Service bulletin
- NHTSA id: 11023283
- Published by NHTSA: 2025\-09\-23
- Manufacturer's number: TSB\_ENG258
- Manufacturer's date: 2025\-09\-13
- Campaign id or software version: SA621
- NHTSA component: ENGINE
- Manufacturer's system: ENG

## NHTSA's summary

TECHNICAL SERVICE BULLETIN: SERVICE ACTION: ECM JUDGEMENT LOGIC IMPROVEMENT FOR DTC P218100 \(SA621\) \- This bulletin provides information to upgrade the Engine Control Module \(ECM\) system software on certain 2025MY K4 \(CL4m\) vehicles produced from July 03, 2024 through April 28, 2025 equipped with an Nu 2.0L MPI engine. The vehicles affected may exhibit a MIL ‘ON’ with DTC P218100 stored under certain driving conditions such as high\-load, high\-speed driving in low temperature environments. There are no drivability or other symptoms associated with this condition. High\-load control logic helps to lower the coolant temperature by allowing the valve of the Integrated Thermal Module \(ITM\) to fully open the radiator port during rapid acceleration.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2025/MC-11023283-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2025/MC-11023283-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Engine

## Trouble codes named

P2181

## Vehicles listed

- 2025 KIA K4

## Recalls for the same vehicles and component

- [25V548000](/recalls/nhtsa/25V548000.md), 2025-08-25: ENGINE AND ENGINE COOLING:CRITICAL FASTENERS

## Other bulletins for the same vehicles and component

- [OTA\_SA621](/bulletins/11026532.md), 2025-12-10, Over\-the\-air update: ENGINE; ELECTRICAL SYSTEM. RELEASE NOTES: OVER\-THE\-AIR: SERVICE ACTION SOFTWARE UPDATE FOR WARNING LIGHTS \(SA621\) \- This Over\-the\-Air \(OTA\) software update is designed to update the Engine Control Unit \(ECU\) logic of certain 2025 K4 vehicles. This update improves the processing logic of the Engine Control Unit \(ECU\) to reduce the unintended display of warning lights.

JSON: [/v1/bulletins/11023283](/v1/bulletins/11023283)

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