U028B: Lost Communication With Active Grille Air Shutter Module C
Standardized SAE J2012 code · U02xx — Lost communication with modules
What does U028B mean?
The vehicle bus reports loss of communication with active grille shutter module C. The aerodynamic flaps in front of the radiator stay in their default position, increasing drag and possibly affecting cooling.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Common causes
- High Bus wiring open or shorted
- Medium Module without power or ground
- Medium Module failed
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of U028B on the same make and model first.
U028B in the community
Ask about U028BNo one has posted about U028B yet
Share your vehicle, the tool you used and what you tested — the first thread helps everyone who searches for this code.
Describe your U028B problem