Powertrain, generic (extended)

P28FA Exhaust Pressure Too Low Bank 2

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P28FA is the bank 2 version of P28F9: the exhaust on the second cylinder bank carries less pressure than the load calls for. It presupposes an engine with a separate pressure reading per bank, such as a V engine with one turbocharger on each side. No manufacturer documents P28FA publicly. The likely chain mirrors bank 1: a cracked manifold or blown gasket on that side, a jammed-open flap, or the bank 2 turbine vanes stuck open. Ford's diesel summary of 2023 compares measured and modelled turbine upstream pressure but treats a mismatch as a sensor error (P0474), so a pure system code like P28FA is not what Ford uses. CARB requires underboost and exhaust system monitoring. A low value only on bank 2 while bank 1 reads normal narrows the search to that side.

Likely causes

Cracked manifold or leaking gasket on bank 2
Bank 2 turbocharger vanes or wastegate stuck open
Exhaust pressure flap of bank 2 jammed open

Symptoms

  • Check engine light on
  • Reduced power and slow boost build-up
  • Exhaust noise or soot traces on bank 2

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–2,500
Time1–6 h

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

Parts involved

exhaust pressure sensor b2exhaust pressure control valve bturbocharger bexhaust system

Related codes

P28F9P28F8P04A4P0299P047B

References: law.cornell.edu, fordservicecontent.com, dieselnet.com.