Powertrain, generic (extended)

P2C9F Fuel Pressure Regulator D Exceeded Control Limits - Pressure Too High

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P2C9F concerns regulator D, which GM uses for the second quantity control valve of a twin high-pressure system. GM's 2023 and 2024 tables 23OBDG07 and 24OBDG07 carry it in an ECM section that also lists the bank 2 rail sensor codes of bulletin 24-NA-106 for the 5.5 L LT6 Corvette. The table entry trips when the filtered rail-pressure control deviation exceeds 3 MPa for 5 s, with a second path while the tank is empty or on reserve, one trip. Note the oddity: this same criterion is the one GM gives bank 1 underpressure code P228C, while P2CA0 receives the mirror image, so the direction printed in the table appears reversed against the code title. In practice the code points to a valve or sensor of bank 2; P2C01 judges the valve's overall authority.

Likely causes

Second quantity control valve (bank 2) not regulating correctly
Water intrusion or fault in the bank 2 fuel harness connector (GM LT6)
Bank 2 rail pressure sensor reading implausibly
Very low tank level causing pressure dropouts

Symptoms

  • MIL on after one trip
  • Rough running or reduced power
  • Further fuel pressure or bank 2 injector codes stored

Repair estimate

DifficultyHardWorkshop job
Parts and labour€150–1,800
Time1–5 h

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

Parts involved

fuel pressure regulator dfuel rail

Related codes

P2CA0P2C9DP2C01P228DP228CP0088

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov, law.cornell.edu.