Network, generic

U028D Lost Communication With Active Aerodynamic Feature Control Module A

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Active aerodynamic features change the airflow around the body while driving, for example an extending front air dam, a movable wing or ride height that drops at speed. CARB defines them as active off-cycle technologies, cites grill shutters and speed-dependent ride height as examples and requires counters that record how long they are deployed. U028D is set when the first control module of such a feature stops sending on the network. No manufacturer documents U028D publicly. The front air dam has its own code: Ram 1500 owners see the check engine lamp with U0645 for lost contact and C0604 for poor function, and FCA's procedure starts with a check for impact damage before cycling the dam with the scan tool. Without the module, the element stays in its last position.

Likely causes

Element or its wiring damaged by kerbs, snow or debris
Water or corrosion at the module connector
Fuse, supply or ground of module A faulty
Control module A internally failed

Symptoms

  • Active aero warning message in the cluster
  • Element does not deploy or retract
  • Slightly higher consumption at highway speed

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–1,500
Time0.3–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

active aero module avehicle bus wiring

Related codes

U028EU028FU0290U0645

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov.