Powertrain, generic (extended)

P228C Fuel Pressure Regulator A Exceeded Control Limits - Pressure Too Low

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P228C means rail pressure has stayed below target long enough that regulator A, the path that sets pump delivery, is judged to have used up its correction. GM uses it widely on gasoline direct injection: in table 25OBDG03A the pump fails to keep up for 10 s within a 12.5 s window, logged as Type A; on its 2018 diesels the margin is 13 MPa with the metering unit in closed loop (Type B), and table 24OBDG07 uses a 3 MPa gap held for 5 s. GM bulletins tie it to pump plungers sticking after heavy E85 use on 2.4, 3.0 and 3.6 L engines (18-NA-072, PIP5385) and to a wrong connector letting water into the bank 2 injector harness of the Corvette LT6 (24-NA-106). Reduced power is common; P228D is the overpressure case.

Likely causes

High-pressure pump or its control valve sticking or worn (e.g. after heavy E85 use)

Low-pressure supply too weak or contaminated fuel

Water or corrosion in the injector or pump wiring

Rail pressure sensor reading too low

Symptoms

Reduced engine power message
Hesitation under load
Check engine light, sometimes clearing after a key cycle

Repair estimate

DifficultyHardWorkshop job

Parts and labour€100–1,800

Time0.5–4 h

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

Parts involved

fuel pressure regulatorhigh pressure fuel pump

Related codes

P228D P229A P0087 P0089 P2C9E

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov.