P0C28: Auxiliary-pump overcurrent must not be confused with feedback duty high

P0C28 is the auxiliary transmission-fluid pump overcurrent report in Ford's architecture table, represented as P0C26_19. It identifies a reported operating category, not the percentage duty cycle of the communication signal by itself.

Check what the signal is reporting

Ford separately diagnoses feedback frequency and low/high duty cycle. The high-duty feedback code is P0C2E, while P0C28 concerns reported pump current. Those two classifications can require different diagnostic questions even though both use the word high in a short description.

The source also separates a stalled-pump report, incorrect speed, and combined current/speed disagreement. Overcurrent alone does not establish which of those other categories is present or prove a particular mechanical restriction.

Preserve the commanded operating state

Record the full code and suffix together with pump command and available reported speed/current status. A measurement taken when operation is not comparable to the original event cannot reconstruct the overcurrent report. If the feedback waveform is invalid, the reliability of the decoded status also needs the applicable diagnostic procedure.

The summary does not provide a universal current limit, winding resistance or justified replacement. It does not authorize applying external power to the pump. Verification must use the matched transmission's pump-control information to isolate the operating fault while keeping communication-format evidence separate.

Source and applicability

Ford 2024–2025 gasoline OBD operation summary, July 16 2024 revision; only the cited monitor and transmission architectures. No individual vehicle fitment or universal calibration is inferred. Ford PDF, page 156. Ford PDF, page 160.