P233F: A regulator supply-high fault is assessed across an off-state driver

P233F is the high supply-circuit code for fuel-pressure regulator B's solenoid. The cited GM strategy tests the high-side driver while it is off. It associates a low voltage across that driver with a connection toward controller power.

Across-driver voltage is not output-to-ground voltage

The source's electrical specification is less than 0.5 Ω between the regulator high-side connection and controller power. A small voltage difference across the off-state driver is therefore consistent with the documented power-directed classification. It should not be confused with a low signal measured against chassis ground.

The assessment requires powertrain-relay voltage above 11 V, active run/crank and an engine that is not cranking. Sixty-one failures within 122 samples are counted on a 6.25-millisecond task, with one-trip reporting. The sample count is separate from any assumption that the fault must remain continuous for a full drive.

Preserve the off-state relationship

Retain command state and both measurement references with the diagnostic result. A normal-looking voltage observed under an on command cannot verify the same off-state behavior. Nor can a fuel-pressure reading establish where the electrical power-directed path occurs.

The table does not identify the regulator, wiring or controller as the failed part, and it does not authorize opening a high-pressure fuel connection. Further isolation must use the correct circuit and fuel-system service procedure for the actual vehicle and calibration.

Source and applicability

2025 GM 04A documented monitor only. Vehicle, engine and controller calibration applicability must be established separately; no model fitment is inferred from the file. GM PDF, physical page 634.