P2B33: Intake profile-actuator open circuit is tested during an on command

P2B33 concerns the intake camshaft profile-actuator drive circuit being classified open. The cited GM row names intake actuator 2; the generic code uses actuator B. This article explains the documented driver without turning those labels into an unverified cylinder or connector location.

Electrical feedback precedes a movement diagnosis

The controller evaluates voltage while the output is powered on. Its implementation-specific thresholds represent an impedance above 200 kΩ toward controller ground. The criterion concerns the output circuit, not direct observation of a cam-profile pin reaching a mechanical position.

A failed movement test and an open-circuit test therefore provide different evidence. If the drive circuit cannot pass its own electrical check, a lack of actuator movement cannot be treated as proof of a mechanically jammed profile mechanism.

Retain the enabled command state

System supply must exceed 11 V, the diagnostic must be enabled, and the ignition switch must be in crank or run. Four failing observations out of five samples establish the row’s result, with one-trip reporting listed separately.

Useful verification aligns the output command with the electrical fault status and supply eligibility. A normal voltage with the driver off does not reproduce the powered-on open-load test. The source does not locate the interruption or establish whether the actuator, harness or output stage is at fault; the correct circuit procedure must separate those possibilities.

Source and applicability

2025 GM 25OBDG03B documented monitor only. Vehicle, engine and calibration applicability must be confirmed from the matching service information; no model fitment is inferred. These criteria explain controller logic, not a complete repair procedure. 25OBDG03B, PDF page 870. 25OBDG03B, PDF page 871. 25OBDG03B, PDF page 872.