Network, generic

U028E Lost Communication With Active Aerodynamic Feature Control Module B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U028E concerns a second aerodynamic control module, B, on vehicles that drive more than one active element or split one element into separately controlled halves. Ford's F-150 is a practical example of the latter: its active air dam has a left and a right actuator whose firmware Ford blamed for C0604 logged by the PCM (SSM 51718), and bulletin 24-2404 and its successors cure the warning Active Air Dam System Fault See Manual and code C0604 with coordinated software updates. Neither Ford nor any other maker publishes U028E or assigns letter B to a specific part. If B drops off the bus while A still works, the elements can end up in unequal positions, and the system usually parks both and shows a warning. CARB treats such features as active off-cycle technology with tracked usage.

Likely causes

Wiring or connector of module B damaged near the moving element
Outdated software in module B or the commanding controller
Supply or ground of module B interrupted
Module B internally failed

Symptoms

  • Active aero or air dam warning in the cluster
  • One side of an element stuck or misaligned

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–1,500
Time0.3–3 h

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

Parts involved

active aero module bvehicle bus wiring

Related codes

U028DU028FU0290U0645

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