U028CLost Communication With Active Grille Air Shutter Module D
- 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
- Module D is the fourth grille shutter address in the code list and only matters on fronts with four independently driven flap units, for instance upper and lower flaps on each side. No manufacturer documents U028C or says where unit D sits, so its position is maker-specific. The surrounding evidence is consistent: Hyundai's 2026 Palisade already splits its lower flaps into left and right actuators and stores U0285 and U028B, with the engine lamp, after water corrodes their plugs (26-01-026H). GM's 2018 engine controller counts a shutter that misses three LIN responses in Run at 11 V or more as a two-trip MIL fault. Under CARB rules, grille shutters belong to the active off-cycle features whose operating time is recorded. A silent unit D leaves its flaps frozen.
- What you may notice
- Check engine lamp on
- Part of the shutters stays open or closed
- Slightly longer warm-up or higher consumption
- Likely causes
- LikelyMoisture or corrosion at the connector of shutter D
- PossibleLIN or supply wire to unit D damaged in the front end
- PossibleActuator D failed, for example after ice or impact
- RareWrong actuator variant or configuration after a repair
- 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.