P2C1FCold Start Fuel 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
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2C1F is the underpressure half of GM's cold-start fuel pressure check on direct-injection petrol engines: while the catalyst is being heated, measured rail pressure lags the target by more than a calibrated margin. Table 25OBDG03B uses a 3 MPa gap for desired pressures from 4 MPa up (2 MPa at 3 MPa), the same map as P228C; 10 s of failures within 12.5 s set the code as Type A, so the MIL lights after one trip. GM's 2019 table 19OBDG03D runs the same check but allows 5 MPa from 20 MPa desired, and table 23OBDG07 (2023) uses a filtered deviation above 3 MPa held for 5 s, also on one trip. Suspects are a weak high-pressure pump or quantity control valve, low feed pressure from the tank pump or a leaking injector. P228C is the same fault outside the warm-up phase, P2C20 the overpressure case.
- What you may notice
- MIL after a single faulty cold start
- Long cranking, rough running or stalling when cold
- Reduced power possible if pressure stays low
- Likely causes
- LikelyHigh-pressure pump with worn plunger or sticking control valve delivering too little
- PossibleLow feed pressure from in-tank pump, filter or pressure regulator
- RareLeaking or sticking injector bleeding off rail pressure
- 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
- Medium · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.