P2C9EFuel Pressure Regulator C 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
- P2C9E is the underpressure counterpart of P2C9D: the circuit run by regulator C cannot reach its pressure target even with the regulator already asking for full delivery. No manufacturer publishes a definition of P2C9E, so the detail comes from analogous codes. GM's 2023/24 tables apply a 3 MPa deviation held for 5 s to its low-pressure codes and add a second path when the tank is empty or on reserve, because fuel starvation can mimic a weak pump. CARB requires such control-limit faults to be detected. Probable causes are a worn high-pressure pump, a valve stuck closed, insufficient feed pressure from the tank pump, a clogged filter or an injector leaking back. Drivers notice hesitation, long cranking or a power cut.
- What you may notice
- MIL on
- Hesitation or stumbling under load
- Extended cranking before the engine starts
- Power limitation
- Likely causes
- LikelyWorn high-pressure pump of circuit C
- PossibleLow feed pressure from the tank pump or a clogged fuel filter
- PossibleQuantity control valve stuck closed or open circuit to it
- RareLeaking injector or rail connection
- 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 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.