U028BLost Communication With Active Grille Air Shutter Module C
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Shutter module C is a third, separately addressed flap actuator behind the grille or bumper, used where a front end divides its cooling air openings into several sections. Hyundai documents the code: its 2026 Palisade and Palisade Hybrid have left and right actuators for the lower active air flaps, and campaign 26-01-026H lists U028B together with U0285 and flap position codes when water enters the bumper connectors and corrodes them. Owners then see an air flap warning, the check engine lamp and sometimes a low oil message; the remedy is to inspect pins and replace harness, actuators or sensors. How the engine controller decides on lost contact is visible at GM, which sets the code for shutters on the LIN bus after three missed responses as a two-trip fault.
- What you may notice
- Check engine lamp on
- Active air flap warning in the cluster
- Lower flaps no longer move
- Likely causes
- LikelyWater ingress and corrosion at the bumper connector of shutter C
- PossibleFront harness damaged by impact, stone chips or poor routing
- PossibleActuator C failed or seized
- RareFault in the controlling engine module or its LIN output
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.