P0661: The intake tuning valve reports an output-one ground-short status

P0661 describes a low intake manifold tuning-valve control circuit on bank 1. The cited GM implementation uses a fault reported by the actuator's power stage: a short-to-ground indication for H-bridge output one. The controller is interpreting electrical diagnostic status, not directly measuring whether the manifold valve is mechanically stuck.

The power stage must be in an eligible state

The battery window is above 9 V and below 17.5 V. The source also requires the relevant power-stage enable state and its stated H-bridge diagnostic status. The reported ground-short condition is evaluated over 0.1 second, with two-trip reporting.

These prerequisites matter when reviewing an apparently quiet output. A driver that is deliberately disabled or operating outside the stated supply window has not necessarily completed the same electrical assessment. The absence of a new code under those conditions is not a demonstrated pass.

Separate output identity from valve position

Retain the output-one fault detail, supply condition and actuator diagnostic state. A manifold position trace can show movement behavior, but it does not independently establish which bridge output reported a ground-directed electrical problem.

The table does not locate that path inside the actuator, harness or controller, and it provides no connector pinout. It also does not justify forcing the tuning mechanism or replacing the complete intake manifold solely because P0661 is present. The exact actuator and circuit procedure is needed to resolve the electrical finding.

Source and applicability

2025 GM 07A-1 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 927; GM PDF, physical page 928.