Powertrain, generic (extended)

P21FD Fuel Control System B Too Rich at Higher Load (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P21FD sets when the second fuel path on bank 1 is still rich at higher load although its learned correction has already taken away the permitted maximum. No manufacturer documents the code publicly. The FCA patent for port plus direct injection engines describes three separate monitors, one per injection mode, so a rich error that appears only while the port system fuels alone can be pinned on that system rather than reported as a general P0172. Possible causes are an air mass sensor reading high at large airflow, a regulator in the low-pressure circuit holding too much pressure, or port injectors that over-deliver at long opening times. Higher fuel consumption and sooty tailpipes may follow. P2192 is the system A counterpart, P21FF the bank 2 code.

Likely causes

Air mass sensor reading too high at large airflow
Low-pressure regulator holding too much pressure
Port injectors on bank 1 over-delivering

Symptoms

  • Check engine lamp on
  • Increased consumption, sooty tailpipe

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–900
Time0.5–4 h

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

Parts involved

fuel injectorfuel pressure regulator

Related codes

P21FCP21FFP21F5P21F9P2192P2BF1

References: patents.google.com, law.cornell.edu, fordservicecontent.com.