P233D: Fuel Pressure Regulator B Solenoid Supply Voltage Control Circuit/Open

Where the ECM switches the solenoid of fuel pressure regulator B on both sides, the ground-side line is checked under P2294 to P2296 and the feed from the high-side driver under P233D to P233F. P233D is the open-circuit code for that feed. No manufacturer documents it publicly: GM's 2025 diesel table 25OBDG04A, where regulator B is the rail pressure regulator valve, contains only the low and high codes of this circuit and folds a broken feed into its regulator tests. The basis is therefore CARB's rule that output components be checked for circuit continuity. An open feed leaves the valve without current regardless of command, so the ECM loses its means of setting rail pressure; depending on the system the pressure rises or collapses, typically with reduced power.

Medium severity. Can I keep driving?Avoid long trips and hard acceleration. If you smell fuel or the car stalls, do not continue.

Symptoms

Check engine light on
Rail pressure not controllable, reduced power
Possibly hard starting or stalling

Most likely causes

Supply wire to the regulator solenoid broken or terminal loose
Corrosion at the regulator connector
Regulator solenoid winding open
High-side driver in the engine control module faulty

What to check, in order

Start with the simplest. You can tick off each step.

Check the pump's fuse, relay, and connector
Check the continuity of the wire between the component and the control module.
Replace the filter if it is due for maintenance
Compare commanded and actual pressure in live data
Measure the pressure with a suitable gauge
Check the sensor and regulator before replacing the pump

Good to know

Repair difficulty: medium
It can trigger limp mode.
It affects emissions.

What each character of P233D means

P: Powertrain: engine and transmission
2: Generic code: same on every make
3: Ignition and misfires
3D: Specific fault in that system

Frequently asked questions

Can I keep driving with code P233D?

Avoid long trips and hard acceleration. If you smell fuel or the car stalls, do not continue.

What causes code P233D?

The most common causes are: supply wire to the regulator solenoid broken or terminal loose; corrosion at the regulator connector; regulator solenoid winding open.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.