P233EFuel Pressure Regulator B Solenoid Supply Voltage Control Circuit 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
- P233E concerns the feed side of fuel pressure regulator B: the line from the ECM's high-side driver to the solenoid is shorted to ground. GM documents it for its 2025 diesels (table 25OBDG04A); there, regulator B means the rail pressure regulator valve. The ECM looks at the voltage across the high-side driver while it is switched on; if that voltage is high, the output is being pulled down, as through an impedance to ground under roughly half an ohm. 61 failures within 122 samples of 6.25 ms, enabled above 11 V and outside cranking, set the code as Type A, MIL in the first trip. The driver normally shuts off to protect itself, so the valve stops working and rail pressure can no longer be held. Ground-side faults use P2294 to P2296; P233F is the short to power.
- What you may notice
- Check engine light on in the first trip
- Reduced power, rail pressure deviation
- Hard starting or stalling possible
- Likely causes
- LikelySupply wire to the regulator rubbed through to ground
- PossibleRegulator solenoid shorted internally or to its housing
- PossibleWater or corrosion in the regulator connector
- RareHigh-side driver in the engine control module damaged
- 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: €60 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.