Kia Carnival Hybrid 2025–2026 — technical service bulletin
Bulletin SC352_TSB · NHTSA communication 11025769 · issued Nov 11, 2025
Technical service bulletin
communication type
Electrical System
component
2025–2026
model years
2
vehicle entries
Official summary
VOLUNTARY SERVICE CAMPAIGN: HVAC SOFTWARE UPGRADE FOR PTC OPERATION LOGIC IMPROVEMENT (SC352) - This bulletin provides information to upgrade the Heating, Ventilation, and Air Conditioning (HVAC) control software on certain 2025-2026MY Carnival HEV (KA4 HEV) vehicles produced from May 16, 2024 through September 8, 2025, to prevent excessive discharging of the 12V battery by the Positive Temperature Coefficient (PTC) heater under certain operating conditions. When the engine is below operating temperature, the PTC heater is used to provide additional heat to the cabin. In very cold environments
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.