P233FFuel Pressure Regulator B Solenoid Supply Voltage Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P233F is set when the feed line of the fuel pressure regulator B solenoid carries voltage even though the ECM has its high-side driver switched off. GM's 2025 diesel table 25OBDG04A describes this test for the rail pressure regulator valve: in the off state the voltage across the driver should be large; if it is low, the line is fed from elsewhere, as if tied to power through less than half an ohm. As with the ground short, 61 failures in 122 samples of 6.25 ms decide, and the code is Type A. A permanently powered feed means the valve can only be controlled via the low side, or is energised continuously if that side is also faulty, so rail pressure may drift from target. Typical findings are a harness touching a battery feed or a damaged connector. P233E is the low counterpart.
- What you may notice
- Check engine light on in the first trip
- Rail pressure too high or unstable
- Reduced engine power possible
- Likely causes
- LikelyRegulator supply wire touching a battery or ignition feed
- PossibleBent or bridged pins in the regulator connector
- RareHigh-side driver in the engine control module stuck on
- 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.