P2C9DFuel Pressure Regulator C Exceeded Control Limits - Pressure Too High
- 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
- P2C9D reports that the fuel pressure in the section governed by regulator C stays above its target although that regulator is already reducing delivery as far as it can. A third regulator letter is only needed where an engine has several pressure control elements, for instance two high-pressure pumps or separate rail circuits. No manufacturer documents P2C9D publicly. The closest published logic is GM's for regulators A and D (tables 23OBDG07 and 24OBDG07): measured and desired rail pressure may differ by no more than 3 MPa for a few seconds before a one-trip fault is stored. CARB demands a fault once fuel pressure control runs out of authority. Expect a hard, noisy idle or reduced power; P2C9E covers the underpressure side of the same regulator.
- What you may notice
- MIL on, often after a single trip
- Harsh or noisy idle, especially when cold
- Reduced engine power
- Likely causes
- LikelyQuantity control valve of circuit C sticking in the delivery position
- PossibleRail pressure sensor of that circuit reading too high
- PossibleWiring or connector fault keeping the valve from being switched
- RareOutdated engine control calibration
- 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 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.