P2C9FFuel Pressure Regulator D 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
- P2C9F concerns regulator D, which GM uses for the second quantity control valve of a twin high-pressure system. GM's 2023 and 2024 tables 23OBDG07 and 24OBDG07 carry it in an ECM section that also lists the bank 2 rail sensor codes of bulletin 24-NA-106 for the 5.5 L LT6 Corvette. The table entry trips when the filtered rail-pressure control deviation exceeds 3 MPa for 5 s, with a second path while the tank is empty or on reserve, one trip. Note the oddity: this same criterion is the one GM gives bank 1 underpressure code P228C, while P2CA0 receives the mirror image, so the direction printed in the table appears reversed against the code title. In practice the code points to a valve or sensor of bank 2; P2C01 judges the valve's overall authority.
- What you may notice
- MIL on after one trip
- Rough running or reduced power
- Further fuel pressure or bank 2 injector codes stored
- Likely causes
- LikelySecond quantity control valve (bank 2) not regulating correctly
- PossibleWater intrusion or fault in the bank 2 fuel harness connector (GM LT6)
- PossibleBank 2 rail pressure sensor reading implausibly
- RareVery low tank level causing pressure dropouts
- 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: €150 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.