P228CFuel Pressure Regulator A Exceeded Control Limits - Pressure Too Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- Reduced engine power message
- Hesitation under load
- Check engine light, sometimes clearing after a key cycle
- Likely causes
- LikelyHigh-pressure pump or its control valve sticking or worn (e.g. after heavy E85 use)
- PossibleLow-pressure supply too weak or contaminated fuel
- RareWater or corrosion in the injector or pump wiring
- RareRail pressure sensor reading too low
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.